US Open: Djokovic in 'constant pain' for weeks with shoulder issue

After ending his US Open defence prematurely, world number one Novak Djokovic spoke of the pain he has dealt with in his left shoulder.

Stan Wawrinka and Novak Djokovic embrace at the end of their US Open clash   -  Getty Images

Novak Djokovic revealed he had been in constant pain for weeks after he retired from his US Open fourth-round match with Stan Wawrinka due to a shoulder injury.

Djokovic received massages on his shoulder at several junctures during his second-round meeting with Juan Ignacio Londero at Flushing Meadows.

However, the world number one appeared in much-improved condition in a third-round win over Denis Kudla on Friday, only for the issue to resurface as Wawrinka dictated Sunday's last-16 clash.

READ : Djokovic's title defence ends, retires from Wawrinka clash

Wawrinka claimed the first two sets 6-4 7-5, with Djokovic receiving treatment prior to the third before conceding defeat following a double-fault that gave the Swiss another break of serve for a 2-1 lead.

After his title defence came to an end, Djokovic told a media conference: "The pain was constant for weeks now. Some days higher; some days with less intensity and obviously taking different stuff to kill the pain instantly. Sometimes it works; sometimes it doesn't.

"[It's] very frustrating. Obviously not the first, not the last player to get injured and to, you know, withdraw from one of the biggest events in sport.

"But obviously I just came off the court, so of course it hurts."

Djokovic was booed off by large sections of the Arthur Ashe Stadium crowd upon leaving the court but refused to blame them for doing so.

"Look, I'm not being offended by, you know, [being] mistreated by anybody," he added. "I don't really pay too much attention on that.

"I like to respect others. I hope that others can respect me and my decision.

"I'm sorry for the crowd. Obviously they came to see a full match, and just wasn't to be. That's all it is.

"A lot of people didn't know what's happening, so you cannot blame them. It is what it is."

READ : Djokovic comes through Kudla test amid continued shoulder questions

- Surprised by Djokovic retirement -

Asked if he could sense something wrong with Djokovic in a rematch of the 2016 final won by the Swiss, Wawrinka told a media conference: "For me, my sense, I was feeling good on the court. I was playing well.

"The more the match was going, better I was playing, I was hitting really hard the ball. I was feeling great on the court. That's the most important.

"For sure I could see some little thing that he was in trouble. But I was most likely, most of the time, focused on myself because I know how well he can fight.

"I know how well he can come back. Doesn't matter how he's feeling on the court, and that's what I was focusing on."

"Yeah, it was," Wawrinka said when asked if the retirement was a shock. "It's always a surprise, for sure, when you play a champion like him.

"You always expect to play against the best of Novak. I saw he wasn't feeling great, but again, it was a surprise, for sure."

Djokovic was booed by large sections of the Arthur Ashe Stadium crowd as he left the court, a turn of events that also had Wawrinka taken aback in New York.

"[I'm] always surprised when you play the number one and you hear the fans booing him when he had to retire, that's for sure," he added.

"He's a good friend. I know him really well. He's [an] amazing champion, and if he has to retire, it's not the best for a tennis player to have to leave the court like that.