Serena to meet Kuznetsova in quarters

Federer will now face France's Gael Monfils. The 11th seed defeated the sixth-seeded American Andy Roddick 6-4 6-2 6-3 later in the evening.

Serena Williams of the United States  serves the ball during the women's  singles fourth round match against  Aleksandra Wozniak of Canada at the  French Open tennis tournament at Roland  Garros in Paris, France, June 1, 2009.  Williams won the match 2-0. (Xinhua/Zhang Yuwei)

As the fourth round continued, Argentinian Juan Martin del Potro faced only one break point as he beat the ninth-seeded Frenchman Jo-Wilfried Tsonga 6-1, 6-7, 6-1, 6-4.

In the women's draw now, second seed Serena Williams was up against Aleksandra Wozniak, but the Canadian number 24 seed offered little resistance. The first set was over in 23 minutes by a 6-1 scoreline. The second lasted just seven minutes longer as Williams booked her place in the quarter-finals 6-1, 6-2.

Williams will now take on Svetlana Kuznetsova in the last eight, the number seven seed beating Poland's Agnieszka Radwanska 6-4, 1-6, 6-1.

And another major upset on the Suzanne Lenglen court. Unseeded 19-year-old Romanian Sorana Cirstea produced the performance of her life to dump out fifth-seeded Jelena Jankovic of Serbia 3-6, 6-0, 9-7.

Jelena Jankovic, said, "You know, we were tied at six-all, you know, and all these games. At the at the end of the day didn't go in my favour. Really tough match and tough loss for me."