he defeated Kevin Anderson in straight sets. In the third round, he then faced David Goffin. Despite winning the first set and leading by a double break in the second set serving at 4–1, he lost the next 5 games and was forced to play a decider, where he lost 2–6. However, the run guaranteed him to match his career-high ranking of No. 7 once again. The following week Monfils entered the 2016 Stockholm Open, where he was seeded first. After receiving a first-round bye, he was upset by Gastão Elias in straight sets. The loss resulted in his ranking dropping down one spot, back to No. 8. Despite missing the penultimate week of the 2016 season, Monfils became the sixth person to qualify for the 2016 ATP World Tour Finals. This year marked his debut at the season-ending event. After falling to Raonic 6–3, 6–4 and losing a 3-set match to Dominic Thiem, Monfils withdrew from the tournament with an injury. Goffin was brought in to replace Monfils for one match. 2017: 400 career singles wins For the whole of 2017, Monfils only managed to progress beyond the round of 16 of the singles main draw in just three ATP World Tour tournaments – the 2017 Open 13 (losing in the quarterfinals to Richard Gasquet), the 2017 Dubai Tennis Championships (losing in the quarterfinals to Fernando Verdasco) and the 2017 Aegon International Eastbourne (losing in the final to Novak Djokovic). In his second round match against No. 5 seed Kei Nishikori at the 2017 Canadian Masters, Monfils saved four match points in the final set tie-break to advance to the third round; he lost his third round match against No. 12 seed Roberto Bautista Agut in three tight sets, losing the last two on tie-breaks. His victory against Nishikori at the Canadian Masters marked the first time in seven years that Monfils had come from a set down to defeat a Top 10 opponent and it was just the third time in his career (3–62) that he had done so. Monfils saw his year-end position in the ATP singles rankings slip to world No. 46 as he struggled with his fitness in 2017. He was forced to withdraw from six tournaments because of various ailments and concluded his season after losing in the third round of the 2017 US Open, citing a right knee injury. 2018: Wimbledon fourth round