Marin Cilic is currently at a career-high ranking of number seven in the world by virtue of a good second half to the season on the ATP World Tour.
The 2014 US Open champion has qualified for the ATP World Tour Finals for the second time in three years, however, 14-time Grand Slam champion's Rafael Nadal withdrawal from the event due to an ongoing wrist injury enhanced Cilic's chances of qualifying in London.
Cilic boasts a respectable 47-21 win-loss record in 2016 along with winning two titles, two runner-up finishes and a quarterfinal finish at Wimbledon for the third consecutive year.
The big-serving Croat was looking to win his second Grand Slam singles title at the Australian Open this year, however, he was unsuccessful in his bid in Melbourne due to suffering a disappointing straight sets defeat at the hands of Roberto Bautista Agut in the third round.
The world number seven reached his first final of the year in February at the Open 13 in Marseille losing to Nick Kyrgios in straight sets. Cilic then traveled to North America to compete at the back-to-back Masters 1000 hard court events at the BNP Paribas Open in Indian Wells, and the Miami Open losing to David Goffin in the quarterfinals and to Gilles Simon in the third round, respectively.
Unfortunately for Cilic, he was non-existent during the clay court season missing the three European Masters 1000 events at the Monte Carlo Rolex Masters, Mutua Madrid Open and Internazionali BNL d'Italia in Rome due to injury. However, the 2014 US Open champion reached the final at his first clay court tournament in Geneva in preparation for the French Open losing to last year's French Open champion Stan Wawrinka in the final. Cilic's lack of matches on clay was evident at the second Grand Slam tournament of the year as he lost to Marco Trungelliti in four sets in the first round.
It was now time for Cilic to transition to grass courts, where Cilic reached the quarterfinals at SW19 for the past two years losing to eventual champion Novak Djokovic on both occasions. However, he recorded two successful results on grass this year losing to Andy Murray in the semifinals of the Aegon Championships and to Roger Federer in the quarterfinals of Wimbledon. Cilic squandered three match points against Federer, which was bitterly disappointing for him as he performed a dominant performance like he did in the semifinals in New York, two years ago.
At the third North American Masters 1000 event at the Rogers Cup in Toronto, Cilic succumbed to his compatriot and fellow big-server Ivo Karlovic in straight sets. This was followed by a three set defeat at the hands of Gael Monfils at the Rio Olympics in the third round, despite winning the first set.
However, Cilic portrayed aggressive tennis at the Western and Southern Open in Cincinnati, recording victories over Viktor Troicki, Fernando Verdasco, Tomas Berdych, compatriot Borna Coric and Grigor Dimitrov to reach his first Masters 1000 final.
The Croat defeated an in-form Murray in the final to clinch his first title of the year, and first Masters 1000 title of his career.
Unfortunately for the Croat, his eight-match winning streak was snapped at the US Open losing to Jack Sock in straight sets in the third round and, it was the former champion's earliest exit before the quarterfinals since 2011.
More positive results were to follow for Cilic at the ATP 500 event in Tokyo defeating Benoit Paire, Fernando Verdasco, Juan Monaco but lost to David Goffin in the semifinals for the third time in his career. Cilic lost to Alexander Zverev at the ATP Masters 1000 event in Shanghai in his opening round match but Cilic returned to the winner's circle in Basel the following week. Mikhail Youzhny, Pablo Carreno Busta, Marcel Granollers, Mischa Zverev and Nishikori all fell by the wayside, and Cilic clinched the first ATP 500 title of his career.
The new world number seven sealed his berth in the Round Robin stage of the ATP World Tour Finals at the final Masters 1000 event of the year at the BNP Paribas Masters in Paris.
Cilic defeated his compatriot Ivo Karlovic in the second round and David Goffin for the first time in four meetings to qualify for London for the second time in three years. The Belgian's chances of qualifying were ended in that loss to a dominant Cilic. However, Cilic scored the biggest win of his career by defeating the three-time defending champion and then-world number one Novak Djokovic for the first time in 15 meetings in the quarterfinals in straight sets. Unfortunately, the Croat was unable to back up his results and lost to John Isner for the first time in seven meetings in the semifinals which snapped his second eight-match winning streak of the year.
Cilic's history at the ATP World Tour Finals
The Croat was drawn in Group A at the ATP World Tour Finals on his debut appearance in London in 2014, a group comprised of world number one Novak Djokovic, that year's Australian Open champion Stan Wawrinka, and Tomas Berdych.
Unfortunately, Cilic finished bottom of his group by getting thrashed by Djokovic 6-1, 6-1, Wawrinka in three sets, 6-3, 4-6, 6-3 and Tomas Berdych in straight sets, 6-3, 6-1.
Cilic is drawn in the John McEnroe group with new world number one Andy Murray, three-time Grand Slam champion and reigning US Open champion Stan Wawrinka, and Kei Nishikori, but the bad news for Cilic is that he has a losing record against all three of his colleagues. Cilic trails 3-11 in his head-to-head meetings with Murray, although the former US Open champion was victorious in their most recent meeting in the final of the Western and Southern Open in Cincinnati.
The Croat trails 2-10 in his meetings with Stan Wawrinka with Cilic's victories over the Swiss, both coming six years ago in Chennai and in the third round of the Australian Open.
The world number seven trails 5-7 in his meetings with Nishikori, although his victories over the Japanese number one have come at Indian Wells in 2008, the US Open on two occasions, Wimbledon this year and in the final of Basel last month.
Cilic's chances of progression
This group is significantly stronger as it is the "Group of Death", and the task will be extremely difficult for Cilic to progress in, however, the world number seven will believe that he can qualify out of this group and reach the semifinals in London for the first time.
The group is wide open and Cilic is capable of beating all three of his opponents when he is on the top of his game. Cilic will need to serve well and remain aggressive on the baseline to advance into the latter stages of the tournament.
Jonas Bjorkman is Cilic's coach since his split with Goran Ivanisevic back in July but the partnership has been successful, and qualifying for the ATP World Tour Finals was one of the goals that Cilic wanted to achieve this season.
The Davis Cup final meeting with Argentina is also on the horizon for Cilic, and this could be a perfect catalyst towards the end of the season for Cilic.