Monday she wore a denim skirt, yesterday black “micro-mini” shorts. No matter the outfit, the result remained the same for Serena Williams: a ho-hum, straight-set victory, 6-4, 6-3.

Williams said she didn’t warm up for very long before her second-round match with Lindsay Lee-Waters, a 27-year-old American who hasn’t played singles here since 1997. With her surgically repaired knee bothering her this summer, Williams said she didn’t want to put too much pressure on herself.

“I didn’t go for too much,” she said. “I just played enough to get what I needed to do.”

Surely, there were signs of the old Serena – a swinging volley winner, a lunge at the net that floated the ball over the charging Lee-Waters. But there were sloppy moments, too, none more noticeable than her failure to hold serve up 2-0 in the second set. Lee-Waters punished two of Williams’s second serves for winners, and then Williams double-faulted to lose the game. Lee-Waters hit deep, hard shots throughout the match, and made it a closer affair than one might have predicted.

Afterward, Williams said she felt good about her serve, which produced eight aces, and wasn’t bothered by her knee. Still, she said that despite being relaxed on the court, her game was not quite where she expected it to be.

“I don’t think I played as well as I did the other night,” she said. “I just think I was kind of blah out there. It was enough today, and obviously with each round I want to get better.”

And without a doubt, each round will bring a new outfit, even if it’s not the most comfortable. “I don’t have to be extremely comfortable, I just want to look, you know, nice out there,” she said.

In the evening match, Jennifer Capriati put a sloppy first-round performance behind her and overwhelmed the at times hapless Magui Serna of Spain, 6-0, 6-2.

Serna, 25, is a lefty with looping topspin strokes well-suited to clay, but she could barely keep the ball in play last night. Capriati won the first eight games, and the match had the look of a grown woman beating up on her kid sister. If they played all night, it seemed, Capriati would win a few dozen sets in a row.

Of the two games Capriati did lose, one, on her serve, ended in a double fault. The other concluded with an ace by Serna.

Asked if she was ready to make a run at the championship, Capriati said, “I think I’m playing good enough.”

Also yesterday, second seed Amelie Mauresmo survived a scare before winning 4-6, 6-2, 6-2.”Pretty bad first set,” she said. “A lot of unforced errors.” In a mild upset, Daniela Hantuchova of Slovakia defeated 17 seed Alicia Molik of Australia.