In a night match delayed for more than an hour by rain, the second-seeded Spaniard found himself on the defensive against Jenkins, a wild card playing in just his fifth ATP Tour level event and second Grand Slam.

"I am very happy to be in the third round. This is my best result here," Nadal said, but he showed little of his usual flair, combatting Jenkins and the tricky winds with a largely defensive approach.

The difficult winds were a theme all day, providing more trouble to most of the seeded players in action than their opponents.

Maria Sharapova, the women's top seed, needed just 49 minutes to subdue 48th-ranked Dally Randriantefy of Madagascar 6-1, 6-0 and reach the third round.

Belgium's Kim Clijsters, seeded fourth but tipped by many as the favorite to lift her first Grand Slam trophy, struggled more in the swirling winds on Arthur Ashe Stadium, but emerged with a 7-5, 6-0 second-round victory over unseeded Colombian Fabiola Zuluaga.

Australian Open champion Serena Williams, seeded eighth, got past Colombian Catalin Castano 6-2, 6-2 to move within one match of meeting her sister, Wimbledon champion Venus Williams in the fourth round as 10th-seeded Venus also advanced with a 6-1, 6-3 victory over Russian Maria Kirilenko.

Indian starlet Sania Mirza battled painful leg cramps to reach the third round matching her best performance to date in a Grand Slam event.

The 18-year-old from Hyderabad defeated Italy's Elena Camerin 6-4, 1-6, 6-4 in a roller-coaster of a match and with France's Marion Bartoli to follow, she will harbour genuine hopes of reaching the last 16 and a likely encounter with Sharapova.

But she will need to fully recover physically from what was a punishing second round tie if is she is to better her breakthrough third round performance at this year's Australian Open where she eventually lost to Serena Williams.

"It was a very strange match and was very up and down," said Mirza who is playing in her first US Open.

"It was very windy today both of us were having a problem. I was just trying to get my rhythm and she was playing some good tennis."

Lleyton Hewitt, the third seed from Australia, was the first to taste the difficult conditions on the Arthur Ashe Stadium in a 6-1, 6-2, 6-1 first-round win over Spain's Albert Costa on Wednesday morning.

"I think I just handled the conditions so much better than he did today," said Hewitt.

The lissome Sharapova joked that she felt she might blow right off the court and into the nearby Unisphere, the giant globe built erected for the 1964 World's Fair that is a landmark at the National Tennis Centre.

Sharapova could afford to laugh after polishing off Randriantefy, who handed her the victory with two of her five double faults on the final two points of the match.

Sharapova advanced to a meeting with Germany's Julia Schruff, who beat American Lisa Raymond 6-3, 6-3.

Clijsters will next face Japanese 30th seed Ai Sugiyama, who defeated Czech Michaela Pastikova 2-6, 6-4, 6-4.

The wind was still up when Serena Williams took the court to open the night session.

But Williams, who is trying to bounce back from various injuries that have hindered her since her Australian Open triumph in January, managed to overcome the conditions and her own 25 unforced errors to book a revenge match with 25th-seeded Italian Francesca Schiavone, a 6-2, 6-2 winner over Finland's Emma Laine.

Venus Williams faces a potentially dangerous third-round match against Slovakian Daniela Hantuchova, the 20th seed who beat Maria Emilia Salerni of Argentina 6-1, 6-0.

Williams, who caused a stir by wearing 40,000-dollar diamond earrings in her first-round match, sported another dazzling dangling pair along with a strand of diamonds around her neck.

Amid the bling, Williams showed a more sober side, pledging a 100 dollars for every ace she hits for the rest of the year to relief efforts in the wake of Hurricane Katrina, which has devastated the Gulf Coast of the United States.