Nadal says US Open failure has been fitness issue

The US Open is the only Grand Slam that world number one Rafa Nadal has yet to win and the Spaniard admits he has found it tough physically to raise himself at the end of the season.

The Open is held at the end of August, when Nadal, a clay court specialist, has often been feeling the strain of the season.

"There are a lot matches for me, a lot of tension in those three months, it's a very important part of season for me and I put everything in there. And after that, it's normal (to) go down," he said.

"In 2002 and 2007 I had problems with my knees...in 2008 I arrived perfect physically but destroyed mentally winning in Roland Garros, Wimbledon, Toronto, the Olympics. So it was crazy for me, a very hard season.

"And last year was another. I broke my abdominal in Montreal, so I played here in Cincinnati with a little bit broken abdominal and with every game, the tear, the abdominal got bigger.

"I finished the US Open destroyed, so for me it was amazing result getting to the semifinal last year," he said.

Nadal is targeting success at this year's event at Flushing Meadows but says he has no clue as to whether his current good form will lead him to finally claim the U.S Open.

"Every year is different. You can be playing very well here and you can arrive there and lose. You can be playing bad here and arrive there and start the tournament slow but get better and better every day and you can finish playing your best tennis and win.

"This year I started Roland Garros playing terribly and finally I played very well in the semifinals and final and win.

"You can do everything perfect but that is not why you are going to win or going to be playing well in that moment," he said.

This year though he expects to be in peak physical condition when he gets to New York, a fact he finds somewhat amusing.

"Physically I'm perfect. Give me two weeks to break everything," he said with a laugh.