Novak Djokovic unhappy with his form ahead of US Open

World No 1 Novak Djokovic has admitted concerns about his own form ahead of the upcoming US Open.

The Serb starts his bid for a third Grand Slam title of the year against Joao Sousa at the US Open on Monday, live on Sky Sports.

Djokovic has already collected trophies at the Australia Open and Wimbledon, but accepts his standards have slipped in recent weeks.

Live US Open Tennis

Since switching to the hard courts in America, Djokovic has suffered a final defeat against Andy Murray at the Montreal Masters, while he was also beaten in the Cincinnati Masters final by Roger Federer.

And the 2011 champion admits that he could be forced to grind out a few results at Flushing Meadows.

"I haven't been happy with the way I played in Cincinnati, except I think the match against Stan in the quarters, that was the best match of the tournament for me," Djokovic told Sky Sports.

"Other than that, I was just holding on, fighting, and winning with that fighting spirit. Not giving up. That's how I reach finals and I thought it was a great result under the circumstances, the way I played.

"That's sport and sometimes you are not able to play as well as you want, but you've got to keep on going and finding a way to win."

Watch live coverage of the US Open on Monday from 4pm on Sky Sports 1.

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