Novak Djokovic’s US Open title defense came to a halt on Sunday when the Serb retired from his fourth-round match against Stan Wawrinka due to a shoulder injury.
Djokovic was trailing against Stan Wawrinka 6-4, 7-5, 2-1 when he quit.
Their meeting on Sunday was the first time since Wawrinka’s victory in the 2016 US Open final, with a trip to the quarterfinals going to the winner.
Wawrinka also beat Djokovic in the 2015 French Open final. The top-ranked Djokovic has 16 major titles, four behind Federer.
Defending US Open champion Djokovic retires injured