Sickly Novak Djokovic unsure how long he can keep going amid health crisis

Just weeks after Djokovic's second-round exit from the Cincinnati Open was marred by vomiting and health issues that required on-court treatment, he suffered the same fate during his defeat to Mariano Navone in the first round in New York.

The 39-year-old once again threw up several times during the Navone clash while he also required medical treatment to his lower back and shoulder.

It was no surprise that his body gave up after more than four hours as he managed to win only one of the last 12 games of the match as the Argentine secured a famous 7-6 (7-5), 5-7, 4-6, 6-2, 6-1.

It was the first time that Djokovic had lost an opening match at the US Open while it is also his first round-of-128 defeat at a Grand Slam since he lost his opener at the 2006 Australian Open.

The 24-time Grand Slam champion refused to go into detail about his health issues after the ATP Masters 1000 event in Cincinnati and once again didn't give too much away when asked about his struggles during his post-match press conference in New York.

"I think it was obvious that it was an awful feeling for me on the court," the former world No 1 said.

"It's something that I've been carrying, unfortunately, pretty much every match this year: vomiting, throwing up, a serious issue there.

"Then my whole body starts to collapse, cramping and pain. The back just gave up in the end, and shoulder, and I couldn't close it out.

"I don't want to take anything away from his victory. Congratulations to him. He's a good guy and a fighter. But I didn't have fun out there."

When asked if he has learned anything about his health issues the past few months, he replied: "I don't know [how I can solve the problem]. I don't want to go into too much detail right now. I'm just trying to understand what's going on and how much longer I can keep going like this."

Djokovic struggled early in the match and ended up losing the opening set and he admitted that he thought about retiring, but once he got a foothold in the match, he was happy to continue.

"Yes, I did, I did [consider giving up]. I did, but then I won a set and then another," he explained. "At that point I said to myself, 'okay, maybe there's a chance.' I didn't want to give up in the fourth or fifth set, I wanted to somehow finish the match."

Unable to turn the tide in the fifth set, Djokovic started crying while 1-3 down and those inside the Arthur Ashe Stadium tried to give him a lift by chanting his name, but it wasn't to be as he failed to win another game.

"The love and appreciation they gave me in the end really touched my heart," the tennis great said.

"They were super nice. So grateful to experience this. When it comes to the match itself and overall feeling of how I felt with my body and playing, it was really not enjoyable. I pretty much despised every moment that I spent on the court for that.

"But from the perspective of the crowd and support, it was incredible, honestly from the beginning. They were trying to lift me up in important moments, and I'm very sorry that I didn't perform as well as I should have or could have or wanted for them."

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