Top seed Victoria felled

Dominika Cibulkova of Slovakia downed top seed Victoria Azarenka of Belarus to pull off a major upset in fourth round action at the French Open on Sunday.

The 15th seed won 6-2, 7-6 (7/4) to set up a quarterfinal match with either Samantha Stosur of Australia or Sloane Stephens of the United States.

Roger Federer reached the quarterfinals on Sunday with a 5-7, 7-5, 6-2, 6-4 win over Belgian lucky loser David Goffin.

The third seed will play either Juan Martin del Potro of Argentina or Tomas Berdych of the Czech Republic for a place in the semifinals.

Azarenka won the Australian Open in January and had been expected to coast past Cibulkova having beaten her seven times out of eight previously.

Earlier, Sara Errani of Italy and Angelique Kerber of Germany both reached the quarterfinals at Roland Garros for the first time with straight sets wins.

"I am getting more mature and more tough mentally," said Cibulkova, explaining that she had learned from the experience of losing to Azarenka in Miami earlier this year when leading a set and 5-2.

"I managed to go through these emotions. She was 6-5 up, and I said, hey, come on, you have to play your game again and just make it.

"And for the tiebreak I'm very, very proud of myself that I was still going for my shots, and I just made it because she would never give me the match."

Errani, seeded 21, defeated Svetlana Kuznetsova of Russia 6-0, 7-5, while 10th seed Kerber ousted Petra Martic of Croatia 6-3, 7-5.

The pair will meet in the last eight in a top half of the draw which had also contained Azarenka.

Errani has been the form player on clay this year winning tournaments in Acapulco, Barcelona and Budapest. She also reached the Australian Open quarterfinals in January on hardcourts.

After a tough opening game, Errani took total control as 2009 champion Kuznetsova struggled to put her game together.

Novak Djokovic staged an epic French Open fourth round recovery to defeat Italy's Andreas Seppi 4-6, 6-7 (5/7), 6-3, 7-5, 6-3 on Sunday and salvage his dream of making Grand Slam history.

The world number one, bidding to become just the third man to hold all four majors at the same time, and first since 1969, struggled in the cold conditions on Philippe Chatrier Court against a player he'd beaten seven times in seven meetings.

"I played very badly, but I won thanks to my fighting spirit," said Djokovic.