Marin Čilić

Marin Čilić ([mâriːn tʃǐːlitɕ]; born 28 September 1988) is a Croatian professional tennis player. Over the course of his career, Čilić has won 18 ATP Tour singles titles, including a Grand Slam title at the 2014 US Open. His career-high singles ranking is world No. 3, achieved on 28 January 2018. Čilić first came to international prominence by defeating world No. 2 Andy Murray in the fourth round of the 2009 US Open, and then reaching the semi-finals at the Australian Open a few months later. He was also runner-up at the 2017 Wimbledon Championships and the 2018 Australian Open, losing to Roger Federer both times. Čilić has reached at least quarterfinal in all four major tournaments, and has made it to at least that stage at 13 different Grand Slams. He is known for his fast serves and powerful ground-strokes.

Čilić started to develop his career at a young age; his first steps of tennis started in Bosnia and Herzegovina. His potential was discovered by local hometown coaches who saw him play and encouraged his move to Zagreb for further training. He was soon befriended by his countryman to be Goran Ivanišević, who introduced him to coach Bob Brett. Čilić turned professional in 2005, and ultimately hired Ivanišević as his full-time coach in 2013. Čilić parted ways with Ivanišević in late July 2016, after advancing to the 2015 Davis Cup semifinals.

Marin Čilić was born in Krstine, Međugorje, a town in Herzegovina region of Bosnia and Herzegovina to Herzegovinian Croat parents. He was raised as a Roman Catholic. His father Zdenko was determined that his sons – Marin and older brothers Vinko and Goran – would have the opportunities he lacked in playing sports. When the first tennis courts in the town were built in 1991, Marin and his friends were among the first to play on them. At the recommendation of Goran Ivanišević, in 2004, at the age of 15, Čilić moved to San Remo, Italy to work with Ivanišević's former coach, Bob Brett. He has a younger brother, Mile, who also plays tennis. On 28 April 2018, he married his long time girlfriend Kristina Milković. They have a son Baldo.

2004–05: Junior circuit

Čilić began playing on the junior ITF circuit in spring 2004. At the start he played on clay courts, winning the La Vie Junior Cup Villach in singles and the Dutch Junior Open in doubles. He then qualified for the 2004 US Open, where he lost in the second round to Sam Querrey. In 2005, he won the French Open title in Boys' singles, beating Andy Murray in the semifinal and Antal van der Duim in the final. He finished 2005 ranked number two behind American Donald Young. While on the junior circuit, he won six tournaments in singles and four in doubles with his Canadian partner, Greg Kates.

Before representing Croatia, he played for Bosnia and Herzegovina as a junior with partner Zachary Rosen.

2004–2007: ATP Tour

In 2004, Čilić played one Futures event (Croatia F1), at which he reached the second round; he finished the year tied at No. 1463 on the rankings of the Association of Tennis Professionals (ATP Tour). He played seven Futures tournaments in 2005, winning one, the Croatia F3 event; two Challenger tournaments, in Zagreb and Geneva; and one ATP International Series tournament, the Croatia Open, where he lost in the opening round. He finished the year ranked No. 587.

In 2006, he played three Futures, winning the Croatia F1 and Croatia F2 events. He also played in nine challengers, nine International Series events (reaching the semifinals at Gstaad), and two Davis Cup ties, against Austria and Argentina. By the end of the year, he was ranked No. 170.

In 2007, he won the first and second professional tournaments of his career: the Casablanca Challenger (in April) and the Rijeka Challenger (in May). In June, at the Queen's Club Championships, he beat Tim Henman in the first round after trailing 2–4 in the final set, and reached the quarterfinals, where he fell to Andy Roddick. After that performance, he reached a new career-high ranking of No. 101 on 18 June 2007.

In the World Group playoffs in the first round of the 2007 Davis Cup, Čilić beat Benjamin Becker of Germany; however, Croatia went on to lose the tie, three matches to two.

2008: First ATP singles title

In 2008, Čilić reached the semifinals at the Chennai Open, in both singles and doubles. In the singles, he was defeated by Mikhail Youzhny, who went on to win the tournament. Čilić made it to the fourth round of the 2008 Australian Open, taking out two seeds on his way, including 2007 Australian Open finalist Fernando González. James Blake beat him in the fourth round. He had achieved his goal for the year of reaching the top 40. His fourth-round result at the Australian Open put him at no. 39 in the ATP rankings.

Čilić also made it to the fourth round of Wimbledon, beating Jarkko Nieminen in five sets in the second round and knocking-out fourteenth seed Paul-Henri Mathieu. At the 2008 Olympics, he reached the second round of the men's singles, beating Juan Mónaco before losing to Fernando González. He lost in straight sets to Arnaud Clément. At the Canada Masters, he defeated Andy Roddick in reaching the quarterfinal stage, giving his best performance in a Masters Series tournament to date. He lost in three sets to Gilles Simon in the quarterfinals.

Čilić played the Pilot Pen Tennis tournament in New Haven, Connecticut, where he won his first ATP title. He defeated Viktor Troicki, Jürgen Melzer, and Igor Andreev in early rounds, then 2007 finalist Mardy Fish in the final. Čilić, seeded for the first time at a Grand Slam, reached the third round of the US Open, but lost to Novak Djokovic in a match that lasted almost four hours. Čilić came back from a break down in each of the second, third, and fourth sets. In the first round, he had defeated Julien Benneteau in five sets in a match that lasted more than four hours, winning the deciding set.

2009: First Grand Slam quarterfinal

Čilić won his first title of 2009 and second career ATP title in the 2009 Chennai Open, defeating first-time finalist Somdev Devvarman.

He reached the fourth round of the 2009 Australian Open after beating David Ferrer in straight sets, equalling his 2008 record. In the fourth round, he was defeated by Juan Martín del Potro in four sets. Later in the year, Čilić won the PBZ Zagreb Indoors, defeating compatriot Mario Ančić in the final. He helped his country defeat Chilean opponents in the Davis Cup first-round tie by winning the opening singles match and joining forces with Mario Ančić to win the doubles rubber.

Čilić reached a career best at the French Open when he beat eighteenth seed Radek Štěpánek in the third round in straight sets. After two competitive sets against the third-seeded Andy Murray, Čilić lost the match.

He reached the second round of the Queen's Club Championships, an ATP World Tour 250 series event, where he was defeated by Nicolas Mahut of France. He beat Alberto Martín to make it into the second round at Wimbledon and won a five-set match (spread over two days) against Sam Querrey. He played another five-set match in the third round against Tommy Haas. He recovered from two sets down, but lost 10–8 in the deciding set, having held a match point.

During the hard-court season, Čilić was defeated in back-to-back events in the first round. At Washington, he was defeated in straight sets by Somdev Devvarman. He then failed to duplicate his quarterfinal appearance in Canada, losing to Mikhail Youzhny. In the 2009 US Open, as the 16th seed, he reached the fourth round, after defeating Ryan Sweeting, Jesse Levine, and Denis Istomin. He defeated Levine after being down two sets to love, coming back to win. He then scored the biggest upset of the 2009 US Open with a straight-sets victory over second-seeded Andy Murray in the fourth round. Čilić outclassed Murray by saving all the break points he faced and took advantage of Murray's unforced errors. After the match, he said it was the biggest win of his career to date. However, in the quarterfinals, he lost to the eventual champion Juan Martín del Potro, despite leading by one set and an opening break in the second set.

Following his impressive US Open run, Čilić participated in the 2009 China Open in Beijing as the eighth seed. He won his opening match against Russian Igor Andreev, followed by a three-set victory over Frechman Julien Benneteau. In the quarterfinals he defeated fourth seed Nikolay Davydenko, before stunning world No. 2 and top seed (in the tournament) Rafael Nadal in a straightforward win. In the final, Čilić went down to second seed Novak Djoković in straight sets.

He reached the fifth final of his career at the 2009 Bank Austria-TennisTrophy as top seed; however, he lost. He received a wild card for the 2009 Davidoff Swiss Indoors, where he finished in the quarterfinals, losing to Radek Štěpánek. His final tournament of the year was the 2009 BNP Paribas Masters. Entered as 12th seed, he came from a set down to defeat Łukasz Kubot in the second round, and then from a set down again to defeat seventh seed Fernando Verdasco, before coming to a halt in the quarterfinals against eventual finalist Gaël Monfils.

2010: First major semifinal and top 10 ranking

Čilić won the 2010 Chennai Open final, beating Stanislas Wawrinka of Switzerland in straight sets.

Seeded 14th at the 2010 Australian Open, he defeated Fabrice Santoro, Bernard Tomic, and Stanislas Wawrinka in the first three rounds. In the fourth round, he faced fourth seed and reigning US Open champion Juan Martín del Potro; it was their third meeting in the past five Grand Slams. In a match that lasted more than four and a half hours, Čilić defeated Del Potro to reach his second quarterfinal appearance at a Grand Slam. In the quarterfinals, he defeated seventh seed Andy Roddick in another five-set victory. In doing so, he became the first Croatian to reach the semifinals at the Australian Open. However, Čilić eventually lost in four sets to Andy Murray, despite winning the first set. Čilić followed up his Australian campaign by defending his title in Zagreb, defeating Michael Berrer in the final. Čilić achieved a new career-high ranking of no. 9 as a result. Čilić was selected to play singles and doubles partnering with Karlović for the Croatia Davis Cup Team against Ecuador in March 2010. Čilić, seeded eighth, lost in the second round to Guillermo García-López at the 2010 BNP Paribas Open.

At the French Open, Čilić lost to Robin Söderling in the fourth round. Čilić was defeated in the first round of Wimbledon by Florian Mayer.

He reached the semifinals of the Legg Mason Tennis Classic in Washington, D.C., ending Mardy Fish's 11-match winning-streak in the third round. Čilić was defeated by eventual champion David Nalbandian.

At the US Open, Čilić lost to Kei Nishikori in the second round.

2011: Sixth ATP title

Čilić began the season with a first-round loss to Kei Nishikori in Chennai, failing to defend his title. At the 2011 Australian Open he progressed to the fourth round, defeating Donald Young, Santiago Giraldo, and then John Isner in a five-set. In the fourth round, he lost to world No. 1 Rafael Nadal. Next, he went to Zagreb to defend another title. Again, he was unable to do so, falling to Florian Mayer in the quarterfinals.

Čilić played next in Rotterdam and lost to Viktor Troicki in the quarterfinals. He then played in Marseille, where he was unseeded. He defeated Tomáš Berdych in the quarterfinals and saved one match point in a comeback win against Mikhail Youzhny. He lost to Robin Söderling in the final. Čilić played for Croatia in the World Group playoffs in the first round of the 2011 Davis Cup, defeating Florian Mayer in the opening singles rubber. He leveled the tie at 2–2 by defeating Philipp Kohlschreiber in the first reverse singles rubber. However, Germany ultimately won the tie.

Čilić lost in the first round of the French Open to Rubén Ramírez Hidalgo and at Wimbledon to his compatriot Ivan Ljubičić.

At Umag, Čilić became the first Croatian man to reach the finals in over 20 years, losing to Alexandr Dolgopolov. He upset Juan Martín del Potro in the second round of the Rogers Cup and reached the third round of the US Open, losing to Roger Federer. In ATP 500 in Beijing, he lost the final against world No. 6 Tomáš Berdych in three sets. The next week he was upset by Albert Ramos in the Shanghai Rolex Masters. He won his sixth career title in Saint Petersburg by defeating world No. 10 Janko Tipsarević in the final. En route to the final, he defeated Sergei Bubka, Somdev Devvarman, Andreas Seppi, and Mikhail Youzhny.

2012: Seventh and eighth ATP titles

Čilić did not play at the 2012 Australian Open, but did play at Indian Wells, where he lost in the second round to David Nalbandian. He was defeated by Juan Martín del Potro in the third round of Miami and the French Open. In June, Čilić won the Queen's Club Championships in London after his opponent in the final, David Nalbandian, was disqualified in the second set for aggravated behaviour, having kicked the hoarding around a linesman's chair, injuring the linesman.

In the third round of Wimbledon, he beat Sam Querrey 7–6, 6–4, 6–7, 6–7, 17–15 in the second-longest match ever played at Wimbledon in 5 hours and 31 minutes. He subsequently lost to Andy Murray in the following round. In July 2012, Čilić became the first home player to win the Croatia Open after 22 years by defeating Marcel Granollers of Spain in the final.

At the 2012 Olympics, he reached the second round in the men's singles, beating Jürgen Melzer before losing to Lleyton Hewitt. In the men's doubles, he reached the quarterfinals with Ivan Dodig.

Čilić was seeded 12th at the 2012 US Open, where he matched his 2009 effort in reaching the quarterfinals. He was defeated by the eventual champion Andy Murray despite winning the first set and leading 5–1 in the second set.

2013: Failed drugs test and ban

Čilić started his year at the Chennai Open, where he lost to Benoît Paire in the quarterfinal. In the 2013 Australian Open he was seeded 12th but was upset in the third round by Andreas Seppi in a five-set match. In February, Čilić played for Croatia in the Davis Cup World Group playoffs against Italy; he defeated Paolo Lorenzi in the opening singles rubber, and in the first reverse singles, he avenged his earlier loss to Seppi at the Australian Open, prevailing in a straight-sets win. Italy, however, won the tie eventually with a final score of 3–2.

At Zagreb, where he had won twice in 2009 and 2010, Čilić won for a third time to earn his ninth career title, defeating Jürgen Melzer in the final. Čilić was top seeded in the Memphis Indoor event but lost to Kei Nishikori, the eventual champion, in the quarterfinals. Čilić next played at Indian Wells, where he lost in the third round to Milos Raonic in three sets. In the following tournament at Miami, he defeated world No. 8 Jo-Wilfried Tsonga in the fourth round but lost to Andy Murray in the quarterfinals.

Čilić started his clay season in Monte Carlo, but lost to Richard Gasquet in the fourth round. In May it was announced Čilić had left his longtime coach Bob Brett and would be coachless at tournaments before hiring a new one. At the French Open, he lost in the third round to Viktor Troicki in straight sets. In June, Čilić returned to Queen's Club to defend his title. He defeated world No. 6 Tomas Berdych in the quarterfinal, his second top 10 win of the year, and Lleyton Hewitt in the semifinal. In the final, Čilić lost to Andy Murray in three sets.

At Wimbledon Čilić pulled out before his second round match claiming he had a left knee injury where he was scheduled to play Kenny de Schepper of France. However, a month later it was revealed that Čilić had pulled out due to failing a drugs test in Munich, allegedly for "incautious use of glucose." On 16 September 2013, he received a backdated nine-month ban due to testing positive for the banned substance nikethamide. Čilić claimed that the banned substance was ingested via Coramine glucose tablets bought at a pharmacy by a member of his team, and as a result the independent tribunal believed that he did not intend to enhance his performance. The suspension ran until 1 February 2014 and all prize money and points since the positive test including the Munich tournament were null and forfeited. Čilić appealed against this ban to the Court of Arbitration for Sport, who reduced the ban from nine months to four months on 25 October. They stated that "the degree of fault committed by the athlete was inferior to that established in the (tribunal) decision and the sanction imposed was too severe in view of the degree of fault". Čilić, whose ranking had dropped to number 47, received an immediate boost as results at the French Open, Queen's and Wimbledon were reinstated.

In late 2013, Čilić started working with Goran Ivanišević as his new coach.

2014: US Open champion

Čilić returned to the tour at Brisbane. He defeated Denis Istomin and Grigor Dimitrov to reach the quarterfinal, where he lost to Kei Nishikori. In Sydney, he lost to Denis Istomin in the second round. At the 2014 Australian Open second round, Čilić lost to Gilles Simon in five sets.

In February, Čilić successfully defended his title at Zagreb without dropping a set, winning his 10th career title. Čilić extended his winning streak at the Rotterdam Open. He defeated Lukas Rosol, world No. 10 Jo-Wilfried Tsonga, world No. 6 Andy Murray and Igor Sijsling, reaching the second final of the season, where he lost to Tomas Berdych. Čilić continued his excellent form in Delray Beach, reaching his third consecutive final of the season, where he defeated Kevin Anderson and won his 11th singles title.

Čilić reached the fourth round of the Indian Wells Masters. He defeated Paolo Lorenzi and Tommy Robredo to set up a clash with Novak Djokovic. However, he lost the match in three sets. His good form came to an end in the Miami Masters where he lost to Édouard Roger-Vasselin in the second round.

During the clay season, Čilić reached the quarterfinals in Barcelona. He lost in early rounds in both Madrid Open and Rome Masters. At the French Open, Čilić reached the third round before losing to Novak Djokovic in four sets.

Čilić returned to Queen's Club in June, where he was last year's runner-up on the grass court, however he was knocked out by Marinko Matosevic in the first round. Čilić successfully rebounded at Wimbledon, reached the quarterfinals for the first time, beating Paul-Henri Mathieu, Andreas Haider-Maurer, Tomas Berdych and Jérémy Chardy before losing to eventual champion Novak Djokovic in five sets.

In July, Čilić played Croatia Open on home soil, where he was defeated in the semifinals by Tommy Robredo. In the warmup US Open Series, Čilić advanced to the third round at Rogers Cup, where he lost to Roger Federer in a close three-set match. In the following Cincinnati Masters, Čilić also reached the third round before losing to Stan Wawrinka.

Seeded 14th at the US Open, Čilić defeated Marcos Baghdatis, Illya Marchenko and Kevin Anderson to set up a fourth round fixture against Gilles Simon, beating the Frenchman for the first time in five matches. He then went on to defeat both world No. 7 Tomas Berdych and world No. 3 Roger Federer in straight sets to reach his maiden grand slam final. This was also his first ever victory against Federer in all competitions. Čilić defeated 10th seed Kei Nishikori in straight sets in the final, claiming his first grand slam title and becoming the first Croatian to win a men's grand slam since his coach Goran Ivanišević won the 2001 Wimbledon Championships. His triumph in the final was also his 300th professional victory.

Following his US Open victory, Čilić played for Croatia in Davis Cup World Group playoffs against Netherlands. Initially signed up for doubles rubber only, Čilić and teammate Marin Draganja beat Robin Haase and Jean-Julien Rojer. After a 2:2 tie between two countries, however, Čilić stepped up and played the deciding fifth singles rubber in place of young compatriot Borna Ćorić, where he defeated Thiemo de Bakker. The victory earned Croatia the World Group status for 2015.

At China Open, Čilić advanced to the quarterfinal before losing to Andy Murray. In Shanghai Masters, Čilić was upset in the first round by fellow countryman Ivo Karlović after losing the tiebreak in the third set. Čilić, however, rebounded at Kremlin Cup, where he defeated Roberto Bautista Agut in the final and won his 4th title of the season. On 18 October, it was announced Čilić, as the then reigning US Open champion, had become the 5th player (after Novak Djokovic, Rafael Nadal, Roger Federer and Stan Wawrinka) to qualify for the ATP World Tour Finals in London from 9–16 November. Čilić subsequently withdrew from the Valencia Open and Paris Masters in order to allow time for an arm injury to heal before the tour finals.He ultimately lost all three matches in the round robin.

Čilić finished the season as world No. 9 in year-end ATP rankings.

2015: 14th ATP title

A shoulder injury prevented Čilić from playing the Brisbane International and Australian Open.

After being sidelined for more than two months, Čilić made his season debut at the Indian Wells Masters. After receiving a bye in the first round, he lost in the second round to Juan Mónaco in straight sets. Čilić subsequently withdrew from the Miami Open due to the shoulder problem. Čilić returned to tour at Monte Carlo Rolex Masters, where he advanced to quarterfinals, before losing to eventual champion Novak Djokovic.

At the 2015 French Open, Čilić lost to David Ferrer in the fourth round in straight sets. At Queen's Club Čilić was beaten in the second round by Victor Troicki in three sets. Čilić matched his 2014 Wimbledon performance, reaching the quarterfinals again after eliminating Moriya, Berankis, Isner (12–10 in the fifth set), and Kudla.

Čilić returned to Flushing Meadows for the 2015 US Open to defend his title, reaching the semi finals where he was beaten in straight sets by Novak Djokovic who also went on to win in the final. Čilić managed to defend his title at the Kremlin Cup, winning the final in almost identical fashion to the previous year. In the final, he defeated the same player as the previous year, Roberto Bautista Agut, by the same scoreline, 6–4, 6–4.

2016: First Masters title and Davis Cup final

In the first major of the year, Australian Open 2016, Marin Čilić was seeded 12, but he was upset by Spain's Roberto Bautista Agut in the third round.

At Indian Wells he reached the quarterfinals before losing to number 15 seed David Goffin. At the Miami Masters he was defeated by Gilles Simon in third round.

At the 2016 Wimbledon Championships Čilić repeated his efforts of the previous two years making the quarterfinals after eliminating rival Kei Nishikori in the fourth round. In the quarterfinals he met third seed Roger Federer; Čilić won the first two sets and had match points in the fourth set but was unable to convert eventually being eliminated in 5 sets.

At the 2016 Olympics, he competed in the men's singles and the men's doubles with Marin Draganja.He reached the last 16 in the singles and the second round in the doubles.

In August 2016, Čilić announced his new coach as Jonas Björkman in a video posted to MyATP. In Cincinnati, Čilić claimed his maiden Masters title, defeating Andy Murray in the final in straight sets. This win ended Murray's 22-match winning streak, dating back to 2016 Queen's Club. The Croat beat Viktor Troicki, Fernando Verdasco, Tomáš Berdych, Borna Ćorić and Grigor Dimitrov in the route to the final. Čilić returned to the top 10 in the following week.

In October, he captured his maiden ATP 500 level title at the Swiss Indoors, beating Nishikori in straight sets in the final. At the 2016 Paris Masters, Čilić defeated Novak Djokovic for the first time in his career to reach the semi-finals, where he subsequently lost to John Isner. His run guaranteed that he would qualify for the ATP World Tour Finals for the second time in three years. There, in the round robin, he lost to Murray and Stan Wawrinka, but defeated Nishikori for his first-ever win at the Finals. With this victory, he rose to no. 6 in the ATP rankings.

In the final of the Davis Cup, with Croatia leading Argentina by 2–1 in matches, Čilić led Juan Martín del Potro by two sets to love needing one more set to win the title for his country. However, del Potro went on to win the match in five sets and Argentina won the deciding match to win the tournament.

2017: Wimbledon final

Marin Čilić started his 2017 season as first seed at the Chennai Open but lost to Jozef Kovalík in the second round. In the first major of the year, the 2017 Australian Open, Čilić lost in the second round to Dan Evans.

In February, he lost in his opening match in Montpellier, reached the quarterfinals of the Rotterdam, and the semifinals of Acapulco.

Čilić was eliminated in the second rounds of Indian Wells, Miami Open, and Madrid Open, but reached the quarterfinals in Rome, and Monte-Carlo. In May, Čilić won the title at the Istanbul Open, defeating Milos Raonic in the final, in straight sets. This was his 14th ATP 250 title, second clay title, and 17th title overall. Additionally, Čilić's victory in Istanbul meant that 2017 was his tenth consecutive year winning at least one ATP title.

Čilić reached the quarterfinal of the French Open for the first time in his career and thus became one of the few tennis players who reached the quarterfinal stage of every Grand Slam.

In June, at the Queen's Club Championships, Marin made the final for the third time in his career. There he faced Feliciano López, losing in three sets, after having a championship point in the final-set tiebreaker. At Wimbledon, Čilić reached the quarterfinals without dropping a set. There, he defeated Gilles Müller in five sets to reach his first Wimbledon semifinal. In the semifinal he recovered from a one set deficit to defeat Sam Querrey in four sets. In the final he was defeated by Roger Federer in straight sets, he struggled with a blister.

An adductor injury forced Čilić to miss the Montreal and Cincinnati Masters events. Čilić returned to play at the 2017 US Open where he lost to Diego Schwartzman in the third round. Despite this, following the tournament's conclusion Čilić broke into the top five for the first time in his career.

In October, Čilić reached the semifinals of the Tokyo, Shanghai, Basel, and the quarterfinals of the Paris Masters. Čilić failed to win a match in the ATP Finals despite going to three sets against Federer, Alexander Zverev, and Jack Sock. Čilić finished the season as world No. 6 for the second consecutive year.

2018: Third Grand Slam final, Davis Cup champion, and world No. 3

Čilić started his 2018 season as first seed in Pune, India. He lost in semi-finals to eventual champion Gilles Simon.

Despite mixed form since his Wimbledon campaign, Čilić defeated world no. 1 Rafael Nadal at the Australian Open after the Spaniard retired hurt in the fifth set, going on to reach another grand-slam final against Roger Federer. This made him the first Croatian to ever reach the singles final at Melbourne Park. He eventually lost in five sets. The match garnered minor criticism from some tennis pundits for being played indoors to favour Federer, despite the Australian Open traditionally being an outdoor event. Čilić later admitted that he found it difficult to adjust to the changed conditions. However, it remained disputed that who among the two players was going to be favored in indoor conditions. At the conclusion of the tournament, Čilić reached a career-high ATP ranking of No. 3. He remained at that position for 12 weeks, before being surpassed by Alexander Zverev.

In the first two Masters 1000 events of the season Čilić was defeated by Philipp Kohlschreiber (at Indian Wells, in the round of 32) and John Isner, the eventual champion of Miami. In the clay court season Čilić played four tournaments reaching the quarterfinals of Monte Carlo, the semifinals of Rome, and the quarterfinals at the French Open. Čilić failed to defend his only title from the 2017 season at Istanbul, losing in his opening match to Malek Jaziri. This defeat marked the first time since February 2014 that Čilić had not held any tournament on the ATP tour.

At Queen's Club, Čilić was the top seed. He reached the final, where he contested a close match with Novak Djokovic, coming out on top in three sets saving match point in the process to claim his second title at Queen's Club and second career win over Djokovic. At Wimbledon, he was drawn in the top half and was considered one of the biggest threats to Roger Federer's title defense. He was upset in the second round by Guido Pella in five sets, after comfortably winning the first two sets.

During the North American summer hard-court swing, Čilić made strong showings in Toronto and Cincinnati, losing in both tournaments to the eventual champion in tight three setters (Rafael Nadal in Toronto and Novak Djokovic in Cincinnati). At the US Open, Čilić recovered from a two set deficit to defeat teenager Alex de Minaur in the third round. Čilić eventually lost in the quarterfinals against Kei Nishikori in a replay of the 2014 final.

Čilić helped Croatia reach the Davis Cup finals for the second time in three years, winning 1 of his 2 singles rubbers against the USA. In October, Čilić suffered a string of early exits at Tokyo, Shanghai, and Basel. He rebounded from this trough in form at the Paris Masters reaching the quarterfinals for a third consecutive year before losing to Djokovic in three sets. By winning a set he ended the Serb's streak of 30 consecutive sets won.

Čilić qualified for the Tour Finals for a third successive time and fourth time overall. His disappointing record at the event continued winning only one of his three round-robin matches, bringing his overall record at the event to 2–10 (16.7%).

Čilić led the Croatian national team at the 2018 Davis Cup final against France on the clay courts of Lille. After comfortably defeating Jo-Wilfried Tsonga in his first match, Čilić found himself in the same position he was in the 2016 final, having to win his second rubber to guarantee Croatia the title. This time however, Čilić defeated his opponent, Lucas Pouille, in straight sets to grab the decisive victory for Croatia.

2019: Struggles with form, fall from top-20

Čilić started his year at Australian Open. In his third round match against Fernando Verdasco, Čilić saved two match points and came back from a two set deficit to advance to the fourth round. This was the seventh time in Čilić's career that he had won a match after being down two sets. In the fourth round, Čilić was upset by an in-form Roberto Bautista Agut.

Over his next three tournaments, Čilić only managed to win one match, while being eliminated early at Dubai, Indian Wells, and Miami. As a result of his poor form in the early hard court season, Čilić fell from the worlds top ten for the first time in over two years.

After another two winless tournaments to start the clay court season (at Monte-Carlo and Budapest), Čilić finally broke his slump at the Madrid Masters by winning three consecutive matches against Martin Kližan, Jan-Lennard Struff, & Laslo Đere on the way to the quarterfinals. However, he had to withdraw before his match against Novak Djokovic due to food poisoning. By reaching the quarterfinals, Čilić became one of the few players on the Tour to reach the quarterfinal stage of all nine Masters 1000 tournaments. Čilić lost his second round match at both Rome and the French Open, to Jan-Lennard Struff and Grigor Dimitrov respectively.

Čilić failed to defend his Queen's Club title, leaving the Croat out of the worlds top 15 for the first time in five years. This also marked the first time since August 2008 that Čilić had not reached a tournament final in over a year. Čilić lost in the second round of Wimbledon to João Sousa in straight sets.

In the North American summer hard-court season, Čilić competed in Washington, Montreal, Cincinnati, and the US Open in New York. Čilić fell from the worlds top 20 after failing to match his previous year's performance at the first three events. At the US Open Čilić reached the fourth round where he showed improvements to form during a four set loss against eventual champion Rafael Nadal.

As of 2018 Čilić plays with the Head YouTek Radical MidPlus with a custom drilled 16x19 string pattern, painted to look like the Head Graphene Touch Prestige Mid. For strings he uses a hybrid of Babolat VS Touch mains and Luxilon ALU Power crosses. He wore Fila apparel until the 2011 season, when he got a 5-year contract with Li-Ning, switching back to Fila in 2016.

Grand Slam singles performance timeline

Current through the 2020 Australian Open.

Finals: 3 (1 title, 2 runners-up)