Novak Djokovic is the best tennis player in the world when healthy but not invincible, especially when playing Stan Wawrinka at the US Open.
Djokovic, the No. 1 seed and defending champion, retired from his fourth round match on Sunday against Vavrinka in the third set because of an apparent left shoulder injury. He had already lost the first two sets and did not look as he usually does when he is well.
Fans whistled at Djokovic as he exited the court, but Vavrinka was much nicer.
"It's never the way you want to finish. match, ”Vavrinka said in an interview with the court. "I'm sorry for Novak. He is a good friend and a great champion.
Wawrinka was the last player to beat Djokovic at the Open in the final in 2016, and he did it again on Sunday. He led 6-4, 7-5, 2-1 when Djokovic stopped the match.
Wawrinka, seeded No. 23, will play No. 5 Daniel Medvedev in the quarterfinals on Tuesday.
Earlier in the tournament, Djokovic said that his shoulder bothers him on his two-sided backhands and the toss of his service. Probably due to his 35 unexpected mistakes in the shortened match.
32-year-old Djokovic has won four of his last five Grand Slam tournaments, including Wimbledon in July. That led to his career total of 16, four behind Roger Federer's record of 20.
In 2016, Wawrinka beat Djokovic in a tough, four-set US Open final. It was the last of the three titles of the Grand Slam of Wawrinka. A knee injury and surgery in 2017 have hampered him in the last few years and his ranking dropped to No. 263 in 2018.
But he went back and entered 2019, ranked No. 66, after which he steadily improved , reaching the quarter-finals of the French Open, where he lost to Federer in four sets.
On Sunday, he played as if he would beat a healthy Djokovic, especially with his overpowering service. Wawrinka earned 84 percent of points in his first serve and also broke Djokovic's serve four times.
Wawrinka is only one player who can benefit from Djokovic's departure. Another is Federer, who did not win the 2008 U.S. Open.
Federer, who beat No. 15 David Goffin earlier on Sunday and will play an unbeaten Grigor Dimitrov in the quarterfinals, now has a potential path in Open that does not include the opportunity to face Djokovic in the semifinals.