Venus Williams was beaten in the fourth round of the French Open by Nadia Petrova 6-4, 6-3 on Sunday, while Roger Federer easily advanced into the quarterfinals on the men's side.

Williams came into the tournament seeded No. 2 behind her sister Serena.

"I'm obviously disappointed," Williams said. "I feel like I had a day where I wanted to hit the ball cross-court and it went down the line. It just wasn't a good day."

Petrova has been a nemesis for the Williams family lately — she beat Serena in the third round at Madrid less than three weeks ago.

Justine Henin rallied in a winner-take-all set that seemed like a final, outslugging Maria Sharapova 6-2, 3-6, 6-3.

In men's play, the top-ranked Federer continued his bid for a second successive title by beating Olympic doubles partner Stanislas Wawrinka 6-4, 7-6 (5), 6-2. Federer will next play No. 5-seeded Robin Soderling in a rematch of last year's final.

No. 4 Andy Murray was upset by No. 15 Tomas Berdych 6-4, 7-5, 6-3.