The world's number one players - Roger Federer of Switzerland and Justine Henin of Belgium - have advanced to the fourth round of the French Open tennis tournament in Paris.

Federer scored a straight-sets win over Italian Potito Starace 6-2, 6-3, 6-0. Federer plays Russian Mikhail Youzhny, who downed 2003 champion Juan Carlos Ferrero of Spain in four sets (6-7, 7-6, 6-2, 6-2).

Henin scored a straight-sets win over Mara Santangelo of Italy (6-2, 6-3). The Belgian, a two-time defending French Open champion, plays Sybille Bammer of Austria next. Bammer beat China's Li Na in straight sets (6-4, 6-3).

Elsewhere in men's third round action Friday, fourth seed Nikolay Davydenko of Russia ousted Michael Llodra of France (6-4, 6-2, 6-4). The Russian faces Argentina David Nalbandian, a four-set winner over Frenchman Gael Monfils (7-6, 5-7, 6-4, 7-6).

Meanwhile, former champion Serena Williams scored a straight-set win over Michaella Krajicek of the Netherlands (6-3, 6-4). Williams plays Dinara Safina of Russia, a three-set winner over Francesca Schiavone of Italy (3-6, 6-3, 6-1).

Ninth seed Tommy Robredo of Spain beat Janko Tipsarevic of Serbia (6-3, 6-4, 6-0). Robredo plays Italian Filippo Volandri, who upset seventh seed Ivan Ljubicic of Croatia in five sets (6-4, 6-7, 4-6, 6-3, 6-4).

In women's third-round play, fourth-seeded Jelena Jankovic of Serbia beat American Venus Williams in three sets, 6-4, 4-6, 6-1. Jankovic takes on France's Marion Bartoli, a straight-sets winner over 13th-seeded Elena Dementieva of Russia (6-2, 6-4).

Italian Tathiana Garbin defeated France's Stephanie Cohen Aloro (6-3, 6-0) to set up a fourth-round match against Nicole Vaidisova of the Czech Republic. Vaidisova scored a 6-4, 6-4 win over Australian Samantha Stosur.

Argentina's Juan Monaco and Guillermo Canas advanced to a fourth-round meeting. Monaco beat Frenchman Edouard Roger Vasselin (6-4, 6-2, 6-4). Canas downed Belgium's Christoph Vliegen (6-2, 6-2, 2-6, 6-3).