By Hal Bock
The Associated Press

Serena Williams warms up before her second-round U.S. Open match against Lindsay Lee-Waters. (AP photo/Richard Drew)

NEW YORK—Wearing what she described as her "micro-mini" outfit, third-seeded Serena Williams advanced to the third round of the U.S. Open on Wednesday with a 6-4, 6-3 victory over Lindsay Lee-Waters.

"It was a great test," Williams said. "She hits the living daylights out of the ball. She was killing everything."

Williams said she felt at ease in the first two rounds of the open, relaxed and calm with nothing to lose.

And as for her outfit—a black, studded tank top and matching tight shorts—she simply smiled.

"I have another surprise for the next match," she said.

Second-seeded Amelie Mauresmo almost got surprised, dropping the first set to Julia Vakulenko. But Mauresmo recovered to win the match 3-6, 6-2, 6-2.

Mauresmo overcame 34 unforced errors and 10 double faults and finished the match with her fourth ace.

"I started very slow in the first set," said Mauresmo. "I'm looking forward to improve my game, because I am not satisfied now."

Gustavo Kuerten, the former French Open champion who was seeded No. 20, was a first-round loser, beaten by Kristian Pless 6-4, 3-6, 6-1, 7-6 (4). Kuerten was done in by 40 unforced errors.

Earlier, fourth-seeded Lleyton Hewitt began his Open with a 6-1, 7-5, 6-4 victory over Wayne Ferreira in the 57th and final Grand Slam tournament for the veteran South African.

Hewitt's Aussie countryman, Mark Philippoussis, a 1998 Open finalist, was forced to retire in the fifth set against Nikolay Davydenko because of trouble with his left hip.