Jelena Jankovic's credentials as a dark horse for the French Open title were further enhanced as she prevailed in a high-quality third-round clash with Venus Williams today.

The in-form Jankovic, the number four seed, claimed a 6-4 4-6 6-1 victory over the American on Philippe Chatrier court.

The Serbian plays either Elena Dementieva or Marion Bartoli in the next round, and with wins in Auckland, Charleston and Rome under her belt already this season, will have to be taken seriously at Roland Garros this year.

Jankovic broke Williams, the 26th seed, in the first game of the match and managed to hold her serve for the remainder of the first set to take it in 30 minutes.

The Serbian's accurate serve caused major problems for Williams, seeking her first singles title at Roland Garros and the sixth major of her career.

But the American hit back at the start of the second set, going 3-0 ahead, before Jankovic pulled it back to 3-2 by forcing a break in the fifth game.

An improving Williams immediately broke back and served for the set at 5-3 up but Jankovic produced a superb game, breaking to 15 despite being forced on the defensive by the sheer power of her rival's groundstrokes.

The Serb ruined her good work by dropping her serve next though, allowing Williams - whose forehand was by that time proving a potent weapon - to level the match.

Jankovic held the whip hand early in the third set after breaking in the third game, Williams smashing a backhand long after saving the first of two break points, and another break in the next service game, following up a double-fault with a wayward forehand, put Jankovic in sight of victory at 4-1 up.

The fourth seed sealed the game on her first match point, as she broke for the third time in the deciding set. Jankovic's best performance at Roland Garros before this year came in 2006, when she perished in the third round.

Roger Federer, the top seed, cruised into the fourth round of the French Open with a routine straight-sets win over Potito Starace.

The Swiss star and world number one dropped just five games in sealing a 6-2 6-3 6-0 victory over the Italian on Philippe Chatrier court.

Federer powered home 34 straight winners in a one-sided clash that lasted an hour and 31 minutes and will take on 13th seed Mikhail Youzhny in the next round following the Russian's four-set win over Juan Carlos Ferrero earlier today.

But Federer is not going to take Youzhny, a semi-finalist at the 2006 US Open and a winner in Rotterdam this year, lightly.

"I think he is a fantastic player," he said. "He's always been very famous for playing exceptionally well in practice but not really tying it together in a match situation.

"Now he's been able to do that, and he's been doing it on a regular basis. That puts him in contention. And he usually plays better against the better players. I have a lot of respect for his game.

"He had a breakthrough late last year at the US Open when he beat Rafa (Rafael Nadal) and played the semis."

Nikolay Davydenko, the fourth seed, moved into the last 16 with a 6-4, 6-2, 6-4 victory over France's Michael Llodra.

Davydenko will face either Argentina's David Nalbandian or Gael Monfils of France for a place in the quarter-finals.

Mens

Singles 2nd rd: Paul-Henri Mathieu (Fra) bt Gilles Simon (Fra) 3-6 6-4 6-1 7-6 (7-2), Igor Andreev (Rus) bt Nicolas Massu (Chi) 6-3 3-6 6-3 7-5

Singles 3rd rd: (1) Roger Federer (Swi) bt Potito Starace (Ita) 6-2 6-3 6-0, Juan Monaco (Arg) bt Edouard Roger-Vasselin (Fra) 6-4 6-2 6-4, (13) Mikhail Youzhny (Rus) bt (17) Juan Carlos Ferrero (Spa) 6-7 (3-7) 7-6 (7-3) 6-2 6-2

Doubles 1st rd: Leos Friedl (Cze) & David Skoch (Cze) bt Ashley Fisher (Aus) & Tripp Phillips (USA) 7-5 6-3, Sergio Roitman (Arg) & Martin Verkerk (Ned) bt Thomas Johansson (Swe) & Jarkko Nieminen (Fin) 6-3 6-7 (3-7) 6-3, (1) Bob Bryan (USA) & Mike Bryan (USA) bt Kristian Pless (Den) & Vincent Spadea (USA) 6-2 6-1, Jeff Coetzee (Rsa) & Rogier Wassen (Ned) bt Albert Montanes (Spa) & Ruben Ramirez Hidalgo (Spa) 6-4 7-6 (8-6), Igor Kunitsyn (Rus) & Dmitry Tursunov (Rus) bt James Auckland (Gbr) & Stephen Huss (Aus) 6-1 4-6 6-2, Fabrice Santoro (Fra) & Nenad Zimonjic (Ser) bt Benjamin Becker (Ger) & Florian Mayer (Ger) 6-0 6-3 Wayne Arthurs (Aus) & Fernando Verdasco (Spa) bt Frantisek Cermak (Cze) & Jan Hajek (Cze) 6-4 6-0 Paul Hanley (Aus) & Kevin Ullyett (Zim) bt Marc Gicquel (Fra) & Florent Serra (Fra) 6-3 6-7 (8-6) 6-3, Jonathan Erlich (Isr) & Andy Ram (Isr) bt Sebastien Grosjean (Fra) & Cyril Saulnier (Fra) 5-7 6-4 6-2

Doubles 2rd: Andrei Pavel (Rom) & Alexander Waske (Ger) bt Chris Haggard (Rsa) & Hyung Taik Lee (Kor) 6-1 6-1, (5) Yung-Jan Chan (Tpe) & Chia-Jung Chuang (Tpe) bt Lourdes Dominguez Lino (Spa) & Arantxa Parra Santonja (Spa) 2-6 6-1 6-1, Yves Allegro (Swi) & Jim Thomas (USA) bt Phillip Kohlschreiber (Ger) & Stefan Koubek (Aut) 6-3 6-1, Mark Knowles (Bah) & Daniel Nestor (Can) bt Thomas Oger (Fra) & Nicolas Tourte (Fra) 6-1 7-6 (8-6), Fabrice Santoro (Fra) & Nenad Zimonjic (Ser) bt Marcel Granollers-Pujol (Spa) & Feliciano Lopez (Spa) 7-5 1-6 6-4

Womens

Singles 2nd rd: (12) Daniela Hantuchova (Svk) bt Olga Poutchkova (Rus) 7-6 (8-6) 6-3

Singles 3rd rd: (4) Jelena Jankovic (Ser) bt (26) Venus Williams (USA) 6-4 4-6 6-1, (19) Tathiana Garbin (Ita) bt Stephanie Cohen Aloro (Fra) 6-3 6-0, (20) Sybille Bammer (Aut) bt (16) Na Li (Chn) 6-4 6-3 (6) Nicole Vaidisova (Cze) bt (27) Samantha Stosur (Aus) 6-4 6-4

Doubles 1st rd: Alona Bondarenko (Ukr) & Katerina Bondarenko (Ukr) bt P Cetkovska (Cze) & Lucie Safarova (Cze) 2-6 6-2 7-6 (8-6), (16) Maria Elena Camerin (Ita) & Gisela Dulko (Arg) bt Corina Morariu (USA) & Patty Schnyder (Swi) 6-4 3-6 7-5, (2) Cara Black (Zim) & Liezel Huber (Rsa) bt Emilie Loit (Fra) & Nicole Pratt (Aus) 6-3 6-4, Mathilde Johansson (Fra) & Selima Sfar (Tun) bt Aravane Rezai (Fra) & Julia Vakulenko (Ukr) 2-6 6-1 6-4, Klaudia Jans (Pol) & Alicja Rosolska (Pol) bt Victoria Azarenka (Blr) & Anna Chakvetadze (Rus) 6-4 6-3, Jarmila Gajdosova (Svk) & Akiko Morigami (Jpn) bt (9) Elena Likhovtseva (Rus) & Elena Vesnina (Rus) 6-3 2-6 6-3 Martina Muller (Ger) & Gabriela Navratilova (Cze) bt Ashley Harkleroad (USA) & Mariya Koryttseva (Ukr) 6-3 5-7 7-5, Eleni Daniilidou (Gre) & Jasmin Woehr (Ger) bt Jill Craybas (USA) & Yaroslava Shvedova (Rus) 6-1 6-4

Doubles 2nd rd: Nuria Llagostera Vives (Spa) & Maria Jose Martinez Sanchez (Spa) bt Su-Wei Hsieh (Tpe) & Shenay Perry (USA) 7-6 (7-1) 6-3, (15) Vera Dushevina (Rus) & Tatiana Perebiynis (Ukr) bt Sophie Lefevre (Fra) & Aurelie Vedy (Fra) 6-1 7-6 (8-6)