NEW YORK — Roger Federer and Rafael Nadal have played each other 21 times over the years, and all over the world.

Eight matches came at Grand Slam tournaments, and seven of those were in finals: three at Wimbledon, three at the French Open, one at the Australian Open.

The rivals never have faced off at the U.S. Open, though, in any year or in any round. A big reason for that: Nadal has yet to make it past the semifinals in New York. He wants a U.S. Open title, of course. It is, after all, the only Grand Slam trophy he has yet to win.

Still, the No. 1-ranked and No. 1-seeded Nadal insists he is not consumed by thoughts of needing to leave Flushing Meadows with a championship two weeks from now.

"I hope I have another chance to play well here and to have the chance to win — but without obsession, no?" Nadal said. "I am more than happy (with) what I have at home, all the tournaments that I won. More than I dreamt five or six years ago."

Only 24 years old, Nadal already owns eight major titles: five French Opens, two Wimbledons, one Australian Open. But he lost in the semifinals at the U.S. Open each of the past two years and only one other time got as far as the quarterfinals.

"There's not much he's doing wrong," Federer said. "If you can make it to the semis, you can make it to the finals. That's pretty clear."

Federer was one of four past U.S. Open champions scheduled to play in Arthur Ashe Stadium on Monday, along with Andy Roddick, Venus Williams and Kim Clijsters. Another previous winner, Lleyton Hewitt, was scheduled.