New York ? Olympic champions Rafael Nadal and Elena Dementieva showed their mettle at the U.S. Open, overcoming early challenges to win Monday in the start of what’s expected to be a wide-open tournament.

Former champs Lindsay Davenport and Svetlana Kuznetsova also opened with straight-sets victories. Many of the stars like to hurry through the first round – it takes seven wins for the title, and any rest is welcome.

Playing for the first time as the world No. 1, Nadal swatted his very first shot wide against No. 136 Bjorn Phau. The Wimbledon and French Open champ was two points from dropping the first set when he surged and, despite needing to bandage a nasty blister, won, 7-6 (4), 6-3, 7-6 (4).

“I didn’t play with normal intensity,” Nadal said. “Probably I’m a little bit tired.”

Asked whether he was more worn down mentally, physically or emotionally from Beijing, he said: “I think it is a little bit of everything.”

Dementieva looked like gold while taking the final four games to defeat Akgul Amanmuradova, 6-4, 7-5. The fifth-seeded Russian was glad to win quickly and give her mind and body a break.

Tenth-seeded Anna Chakvetadze was the top player to lose, beaten by Ekateria Makarova, 1-6, 6-2, 6-3, in a matchup of Russians.

Roger Federer, bidding for his fifth straight U.S. Open title, was scheduled to begin today, as were No. 1 Ana Ivanovic and the Williams sisters.