MIAMI (Florida) (AFP) Roger Federer had to dig deep to win a pair of tiebreaks but Svetlana Kuznetsova was not so lucky as the womens top seed was sent crashing out of the ATP and WTA Sony Ericsson Open on Monday. Reigning Australian Open, French Open and Wimbledon champ Federer swept past Frances Florent Serra 7-6 (7/2), 7-6 (7/3) in a third round match. Serra made top seed Federer work for the win as the Swiss star had his service broken three times and he made two costly double-faults. Federer also committed 35 unforced errors to 32 for Serra. But Federer closed out the win with a service winner as he played well in both tiebreakers on the hardcourts at Crandon Park. All in all, Im thrilled to be through, Federer said. At the end of the day, thats what counts. Watching from the stands on Monday was Spaniard Rafael Nadal, who could meet Federer in Sundays final. It has always been a lot of fun playing against him, Federer said. I hope that day is going to come soon again. Federer won the Key Biscayne title in 2005 and 2006. His 36 career victories in the event is third behind Pete Sampras and Andre Agassi. In the womens side of the draw, top seed Kuznetsova crashed out of the tournament after suffering a 6-3, 6-0 fourth round loss to former Wimbledon finalist Marion Bartoli of France. Kuznetsova, who won here four years ago, received on-court treatment for a nagging shoulder injury three times in Mondays match. I almost had stars in my eyes, it was so painful, said Kuznetsova, who won just eight points in the second set. I cannot return. Then I cannot serve. In the evening match, Justine Henin of Belgium breezed past Russian Vera Zvonareva 6-1, 6-4. Bartoli claimed her first win in three meetings with the Russian and advanced to the Miami quarter-finals for the second time in her career. She has now won seven of her past 11 matches against top five players. Im just trying to stay positive each day and go on the court and practice as well as I could and just get on the court and play my tennis and see how it goes, said 13th seeded Bartoli. Obviously this week is working pretty well. American Mardy Fish advanced to the fourth round with his second straight win over a seeded opponent, beating No. 29 Feliciano Lopez 7-5, 6-3. Fish upset defending champion Andy Murray in the second round. Federer needed 92 minutes and six aces to dispatch Serra in their first career meeting. He won eight straight service points in the tiebreakers. Federer advances to face No. 16 Tomas Berdych, who beat Horacio Zeballos 6-4, 7-5. Federers 7-6, 7-6 win was his first since 2008. He played just four tiebreakers in his 14 previous matches this year, winning two. Its nice having won two breakers, he said. That doesnt happen every match you play. Third seeded Venus Williams won the final seven points as the American rallied to beat Daniela Hantuchova 1-6, 7-5, 6-4 to reach the quarter-finals. I was a little bit off and struggling to find the court, said Williams, the only American to reach the round of 16. Of course Id like to win more straightforward, but when it counts and times get tough, I always feel confident that Im going to find a way to win. Williams smashed service winners on the opening two points of the final game. Williams is looking for her fourth Miami title and her first in nine years. She advances to face Agnieszka Radwanska, who beat Yaroslava Shvedova 6-1, 6-4. Like Kuznetsova, defending champion Victoria Azarenka also lost on Monday as former world number one Kim Clijsters easily beat Azarenka 6-4, 6-0. Clijsters, seeded 14th, next plays Australian Samantha Stosur, who surprised seventh seed Jelena Jankovic 6-1, 7-6 (11/9). Beating Hantuchova is old hat for Williams, who has won all 10 of their contests. But she was not in top form committing 45 unforced errors, including 11 as she lost the first four games. Days like this, you just have to figure out a way to win the point, even if its not pretty, Williams said. I enjoy that battle.