Spain's Rafael Nadal reacts during his quarterfinal match against Mardy Fish of the US at the Cincinnati Open in Cincinnati, Ohio, on Friday. [Photo/Agencies]

MASON, Ohio - The once dominant top two in men's tennis, Roger Federer and Rafa Nadal, head into the US Open with much more than the formidable year of world No 1 Novak Djokovic to concern them.

Federer and Nadal exited the Cincinnati Open at the quarterfinal stage on Friday after suffering defeats to Czech Tomas Berdych and American Mardy Fish respectively.

While neither of those losses can be considered massive upsets, Fish being an accomplished performer on hard courts and Berdych a two-time winner over Federer last year, there were worrying aspects to both losses for the Spaniard and the Swiss.

Nadal, who was knocked out in the second round in Montreal last week, does not like to make excuses and regularly downplays injuries, but whether his foot troubles are purely run-of-the-mill blistering or a more serious problem, he does not appear to have the sharpness and pace that has been key to his game.

To add to that, he has two nasty burns on the fingers of his right hand from an accident in a restaurant earlier this week when he was given a hot plate that left him in agony.

Nadal's defeat to Fish may also have been influenced by a hectic day on Thursday in which he played a 3 1/2 hour three-setter against compatriot Fernando Verdasco and then kept his commitment to play in the doubles.

Friday's loss aside, the dynamism that is central to Nadal's success is not there at the moment and he needs to find it in the next two weeks if he is to defend his title at Flushing Meadows.

"Sometimes you are playing well; sometimes you are playing worse. I am playing a little bit worse now than well, so I accept the loss and work hard - that's the only way to come back to my best level," said Nadal.

"My movement wasn't perfect, I made more mistakes than usual with the forehand. I have to play more inside the court, more aggressively," he said.

"I have a few things to improve if I want to be ready for New York. I am going to work on that. I don't know if I will be in perfect condition in New York, but, for sure, I will try everything."

In contrast, Federer looked fresh and relaxed this week before coming unstuck against Berdych's big serve in a repeat of his losses to the Czech at Wimbledon and Miami last year.

There have been signs that the old Federer, the fluent and confident player who won with such elegant ease in his heyday, is not beyond the reach of the 30-year-old.

Reuters