Former champs Lindsay Davenport and Svetlana Kuznetsova also opened with straight-sets victories.

Playing for the first time as the top-ranked player on the ATP tour, 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 fatigued mentally, physically or emotionally from Beijing, he said: "I think it is a little bit of everything."

Nadal got a stiffer test from the German qualifier than many anticipated, and shook his head near the end of a match that lasted nearly three hours.

No. 9 seed James Blake had to play past midnight to survive a five-set match against fellow American Donald Young. Blake won 6-1, 3-6, 6-1, 4-6, 6-4.

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.

"It's very hard not to think about the Olympic Games," Dementieva said. "Very difficult to refocus. I mean, all my thinking is there in Beijing."

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 US Open title, was scheduled to begin late last night, as were No. 1 Ana Ivanovic and the Williams sisters.

The final Grand Slam of the season figured to be a scramble on both sides.

Nadal seems like the favorite, yet has never gone beyond the quarterfinals in five previous tries at Flushing Meadows.

The women's draw is even more tricky.

Six different women have won the US Open in the last seven years, and Dementieva is seeking her first major championship. To her, the Olympic singles title counts.

"The biggest goal for the year was Beijing," she said. "In Russia, if you stop anyone in the street and ask what is a Grand Slam, I don't think many people can tell you. But everyone knows the Olympic Games. There is nothing bigger."

No. 2 seed Jelena Jankovic of Serbia advanced with a 6-3, 6-1 victory over American CoCo Vandeweghe.

The No. 23-seeded Davenport defeated Aleksandra Wozniak of Canada 6-4, 6-2.

No. 8 Vera Zvonareva of Russia, No. 12 Marion Bartoli of France, No. 14 Victoria Azarenka of Belarus and Swiss No. 15 Patty Schnyder also won. No. 22 Maria Kirilenko of Russia lost to Austria's Tamira Paszek 6-3, 3-6, 6-4.

On the men's side, fourth-seeded David Ferrer of Spain beat Martin Vassallo Arguello of Argentina 7-6 (1), 6-2, 6-2. British sixth seed Andy Murray smacked around Argentine Sergio Roitman in a 6-3, 6-4, 6-0 mauling.

Also winning were No. 7 David Nalbandian of Argentina, No. 10 Stanislas Wawrinka of Switzerland, No. 16 Gilles Simon of France and No. 17 Juan Martin del Potro of Argentina.

Spanish No. 27 Feliciano Lopez lost to Jurgen Melzer of Austria 4-6, 7-6 (5), 6-2, 2-6, 6-4. The No. 29-seeded Juan Monaco of Argentina lost an entertaining battle to Kei Nishikori of Japan 6-2, 6-2, 5-7, 6-2.