Federer wary of Nadal threat at US Open

Roger Federer goes into this week's US Open as the overwhelming favourite as he bids to become the first man in the modern era to win the title for a fourth consecutive time.

But though he is high on confidence after winning his 50th career title in Cincinnati last weekend, the world number one has one name nagging away at him... Rafael Nadal.

Victory in New York would not only make Federer the first man since American Bill Tillden in the 1920s to win four titles in succession, it would also see him win three of the four grand-slam events for the third time in four years.

A 12th grand-slam crown is also on the line for Federer, just two short of the record held by Pete Sampras. The Swiss had no doubts about who will be his main rival over the next two weeks.

"Even though now people talk about Djokovic, for me Nadal is better, a lot better to be honest," Federer said.

"If I don't win the US Open I expect him to win it."

Djokovic beat both Nadal and Federer to win the Montreal Masters the week before Cincinnati but Federer said the Spaniard was a cut above the rest.

"There's no such thing as a specialist on clay now. Maybe it's your best surface but then you can always play well on the hard courts, and even grass today," he said.

"That's why I am not surprised at all at how good Nadal is. It's almost impossible for him to be as dominant on hard courts as he is on clay because hard courts is just a different ball game, but it (his main rival) is Nadal."