PARIS — Rust-colored flecks of clay dotted Andy Roddick's white attire, from the brim of his baseball cap, down the back of his shirt, to his ankle braces.

Never before this comfortable at the only Grand Slam tournament played on the sport's slowest surface, Roddick reached the French Open's fourth round for the first time in his career by beating Marc Gicquel of France, 6-1, 6-4, 6-4, yesterday.

And the sixth-seeded Roddick is not satisfied, even though his performance so far is quite an upgrade for someone who hadn't won a match at Roland Garros since 2005.

"Any time you accomplish a goal, it's nice. But my tournament is not over. You know, I'd like to keep going," the American said. "I don't even have anything else to do next week. I'd like to stick around."

He's one of only two U.S. singles players, out of 17 men and women entered, who will compete in Week 2. The other is Serena Williams, the 2002 French Open champion, who lost a disputed point en route to dropping the opening set yesterday, but came back to defeat Maria Jose Martinez Sanchez, 4-6, 6-3, 6-4.

Afterward, Williams branded Martinez Sanchez a cheater for failing to fess up that a ball ricocheted off her arm. Martinez Sanchez said the ball went off her racket. NBC replays appeared to show the ball went off the Spaniard's arm, then her racket, on its way over the net; rules call for a player to lose the point if she touches the ball.

"She should have lost the point — instead of cheating," Williams said.

During a changeover in the third set of Williams' match, the scoreboard at Court Suzanne Lenglen displayed results from other arenas. First, it showed that two-time semifinalist and fourth-seeded Novak Djokovic was on his way to being upset by No. 29 Philipp Kohlschreiber of Germany, 6-4, 6-4, 6-4. Then the scoreboard showed three-time runner-up and second-seeded Roger Federer dropping the first set against France's Paul-Henri Mathieu.

But if Djokovic never got things turned around, Federer most certainly did, and he wound up wrapping up a 4-6, 6-1, 6-4, 6-4 victory over the 32nd-seeded Mathieu.