Sam Stosur ended Justine Henin's hopes of a comeback victory at the French Open by converting a second match point Monday for a 2-6, 6-1, 6-4 fourth-round victory, while Rafael Nadal and Novak Djokovic were winners at the same stage on the men's side. Needing one point to secure the upset win, Stosur wavered and hit a double-fault. The Australian player took a deep breath and tried again, this time launching a confident serve into the corner which set her up for an overhead slam to seal the biggest victory of her career. Stosur ended the four-time French Open champion's streak of 24 consecutive victories at Roland Garros and will play in the quarterfinals top-ranked Serena Williams, who beat Shahar Peer 6-2, 6-2. Nadal, another four-time champion, advanced by beating No. 24-seeded Thomaz Bellucci 6-2, 7-5, 6-4. The Spanish player, who lost in the fourth round in 2009, has yet to drop a set in this year's tournament and will next play compatriot Nicolas Almagro, seeded 19th. Third-seeded Djokovic eliminated the last American in the men's draw, Robby Ginepri, 6-4, 2-6, 6-1, 6-2. Henin's defeat was her first in the tournament since 2004. She was seeded 22nd and playing at Roland Garros for the first time since ending a 20-month retirement, looking like a title contender in the early rounds. But after taking a 4-3 lead in the final set against the No. 7-seeded Stosur, Henin showed signs of nerves and was betrayed by her elegant backhand. Serving at 4-4, the Belgian player double-faulted to reach break point, then yanked a backhand wide. In the final game, she pushed three backhands into the net, including a potential putaway on the first point. “My nerves were simply not strong enough,” said Henin, forced to play for a fifth consecutive day because of weather interruptions. “I felt very nervous, very upset, which is normally not the way I am.” In the final two sets, Stosur had a 20-8 edge in winners and converted four of five break-point chances. As for that double-fault on the next-to-last point, she said: “I just tried to shake it off and tried to have a laugh at myself, not worry about it and get the next one in.” Serena advanced easily, looking shaky only after her fourth-round victory, when she tried to speak French to the crowd. “I get so nervous,” she told the interviewer with a giggle in English when she was done. Otherwise, she advanced smoothly to the quarterfinals. Stosur's win spoiled the prospect of a showdown between longtime rivals Serena and Henin. “You can never underestimate anyone, and Sam is actually a wonderful clay-court player,” Serena said. “She's someone you can't overlook.” Elsewhere, No. 4 Jelena Jankovic committed only 11 unforced errors in her 6-4, 6-2 defeat of No. 23 Daniela Hantuchova, and will meet unseeded Yaroslava Shvedova in the quarterfinals. Against Djokovic, Ginepri was serving at 0-1 in the third set when he went down face-first chasing a shot. He made the most of his awkward court position by doing push-ups, but lost the next two points to lose serve, and won only three games the rest of the way. Djokovic's next opponent will be No. 22 Jurgen Melzer, a first-time Grand Slam quarterfinalist playing in his 32nd major event. The Austrian advanced by beating qualifier Teimuraz Gabashvili 7-6 (6), 4-6, 6-1, 6-4. Almagro beat fellow Spaniard Fernando Verdasco 6-1, 4-6, 6-1, 6-4. Shvedova became a Grand Slam quarterfinalist for the first time by beating wild card Jarmila Groth 6-4, 6-3. Serena and Venus Williams, meanwhile, advanced to the semifinals of the doubles tournament. The siblings defeated Maria Kirilenko and Agnieszka Radwanska 6-2, 6-3 Monday. The Williamses won the doubles title in Paris in 1999.