Roger Federer teased, Lleyton Hewitt shone and Serena Williams dazzled at the U.S. Open on Wednesday, although the bronze medallists at the Athens Olympics were both upset.

Playing under lights, world number one and top seed Federer was given a scare by Cypriot qualifier Marcos Baghdatis, last year's leading junior, before battling through to the third round 6-2, 6-7, 6-3, 6-1.

The 19-year-old Baghdatis, who became the first Cypriot to win a Grand Slam singles match when he beat Olivier Mutis in the first round, showed huge ability as he pushed the Swiss harder than expected.

"It was tough," Federer admitted. "He took his chances in the second set and really got into the match.

"It was going easy for me, he was making mistakes, but I definitely let him into the match and he took advantage, so good for him."

The humidity of the opening two days was replaced by sunny skies and the in-form Hewitt romped to a 6-1, 7-5, 6-4 first round victory over Wayne Ferreira, who was playing in a record 56th consecutive, and last, Grand Slam event.

"Knowing it was his last Grand Slam made it a little tough out there," Hewitt said.

"Winning a lot of matches, though, gives you a lot of confidence and in the last few weeks, I think I've played as well, if not better than when I won here (in 2001)."

If Hewitt was the most impressive player on show, Serena Williams again grabbed the attention with another outfit.

Dressed in a black, jewel-encrusted two-piece, Serena's powers failed her briefly when she let slip a 4-2 lead in the first set as world number 86 Linda Lee-Waters levelled at 4-4.

The third seed and two-time champion stepped up her game to win 6-4 6-3 and reach the third round.

"These two matches I have felt like I have nothing to lose and I am really calm," Serena said.

TENTATIVE SEEDS

Second seed Amelie Mauresmo was at her tentative worst in the first set of her match with Julia Virilenko of Ukraine but rebounded to win 3-6, 6-2, 6-2 and reach the third round.

"It's been a long summer and I have to be careful to make sure I am focused, and that my feet are moving properly," she said.

Sixth seed Elena Dementieva stuttered into the third round despite serving eight double faults in her 6-3, 6-2 win over French qualifier Severine Beltrame, but Australian Alicia Molik became the highest-ranked woman to exit.

The 17th seed, who picked up the bronze in Athens, was beaten 6-4, 6-3 by former world number five Daniela Hantuchova, who now plays Swiss 15th seed Patty Schnyder.

"I don't know what it is but I find it really difficult to play against her," Hantuchova said. "But if I play like I did today, I think I have a pretty good chance.

Bulgarian 22nd seed Magdalena Maleeva was another early casualty, beaten 6-3, 6-2 by 19-year-old American wildcard Angela Haynes.

There was disappointment for another Australian, Mark Philippoussis, who retired with hip trouble when trailing Nikolay Davydenko 4-1 in the final set.

"It was a spasm or something," he said. "I couldn't push up on my serve. I've never had anything like this. I was feeling great out there. It came out of nowhere.

"It's pretty much the worst year of my tennis career so far. I feel like I just want to start all over again."

In other men's matches, eighth seed David Nalbandian eased past Dutchman Dennis van Scheppingen, while Sebastien Grosjean and Vince Spadea were other seeds to advance.

However, three-time French Open champion and 20th seed Gustavo Kuerten was beaten in four sets by Kristian Pless of Denmark.

Fernando Gonzalez of Chile, the 14th seed and Olympic bronze medallist, Argentinean Juan Ignacio Chela and Swede Jonas Bjorkman, the number 32 seed, also lost.