2014 US Open champion Marin Cilic is on the cusp of qualifying for the ATP World Tour Finals for the second time in his career and the Croat will be hoping to finish 2016 on a high with the Davis Cup final also on the horizon.
David Goffin has an outside chance of qualifying for the ATP World Tour Finals for the first time in his career but he will most likely need to win the title and hope his fellow hopefuls fall by the wayside early.
Goffin is enjoying a career-best year by reaching the top ten for the first time in his career along with reaching his first Grand Slam quarterfinal at the French Open, which was the tournament he made his breakthrough four years prior.
Cilic is no longer working with Goran Ivanisevic, who is now the coach of Tomas Berdych, and the Czech is breathing down Cilic's neck for the final qualifying spot in London.
The Croat is now working with Andy Murray's former coach Jonas Bjorkman.
How they got here
All seeds received a bye in the first round, and the ninth seed began his campaign against compatriot and Davis Cup teammate Ivo Karlovic.
The former US Open champion lead 2-0 in his series with Karlovic but he lost the last two encounters, however, Cilic was victorious in straight sets, 7-6 (7), 6-2 to defeat Karlovic for the first time since 2011.
Meanwhile, Goffin defeated big-serving Frenchman Nicolas Mahut, 7-6 (5), 6-3 to keep his faint hopes of qualifying for London alive.
The two top ten seeded players will do battle for the fourth time this year, and it is the Belgian who has a flawless 3-0 head-to-head record over Cilic.
Goffin won their first meeting in the Davis Cup on clay in Belgium with a 6-4, 6-4, 3-6, 7-5 victory, however, Croatia went on to win the tie and they will be contesting the final with Argentina later this month.
This year's French Open quarterfinalist reached the semifinals of a Masters 1,000 event for the first time in his career at the BNP Paribas Open in Indian Wells with a 7-6 (4), 6-2 victory over Cilic.
Goffin once again got the better of Cilic in the semifinals of the 500 event in Tokyo with a 7-5, 6-4 victory.
Who reaches the quarterfinals?
Cilic is full of confidence at the moment after claiming his first title at an ATP 500 event in Basel by defeating Kei Nishikori in the final, displaying scintillating tennis indoors.
Playing indoors suits Cilic's game with the big serve and his forehand is a ferocious weapon once it's firing on all cylinders.
However, Cilic has struggled to contain Goffin because the Belgian is able to get the Croat in uncomfortable positions, and the eighth seed is speedy around the court.
Goffin also possesses a two-handed right-handed backhand which generates a lot of power and uses it frequently on important points in a match.
Both players are good returners and they can constantly put pressure on their opponent's service games, of course, Cilic is the better server but Goffin has had joy in the past of breaking the Croat's serve.
Dominic Thiem's currently in the penultimate spot for London but he lost to Jack Sock in his opening match, and Cilic currently occupies the final spot.
This is a must-win match for Goffin in Paris, and both players will be under a tremendous amount of pressure in this encounter which should make it an interesting spectacle to watch.
This is the first match scheduled on Court Central at 11am local time, and the winner of this match will face top seed and three-time defending champion Novak Djokovic or 14th seed Grigor Dimitrov in the quarterfinals.
Prediction: Cilic in three sets