India, Aug. 31 -- The US Open witnessed a major upset as Novak Djokovic suffered a shock first-round defeat, sending millions of his fans into disbelief.

Djokovic was knocked out of the tournament by Argentina's Mariano Navone, who gave the Serbian legend few opportunities to fight his way back into the match.

In a dramatic and physically demanding clash, Djokovic appeared to struggle physically and was even seen vomiting into a towel bin during the match.

The defeat marked the first time Djokovic had been eliminated in the opening round of the US Open.

Reflecting on the difficult match, Djokovic was quoted by the BBC as saying: "I think it was obvious that it was an awful feeling on the court for me."

"I don't want to take too much ...