Paris:  Top seed Rafael Nadal and fourth seed Andy Murray both reached the last 16 of men's singles in  the French Open on Saturday.

The 24-year-old Scot, Andy Murray, had been coasting along at 6-2, 2-1 and deuce on German Michael Berrer's serve when he jarred his right ankle badly trying to run down a drop shot.

Murray won the point, but he hopped about in agony and then collapsed onto his back in the red dirt of the Suzanne Lenglen showcourt.

After taking painkillers and having the ankle strapped at a medical time-out, Murray resumed clinching the break and leading 3-1.

Murray took the set 6-3 to go two sets up, but he still looked in some discomfort and requested another medical time-out from the umpire at the next change of ends.

Murray duly wrapped up a third straight sets win, but there will be serious doubts about his fitness ahead of his fourth tie against Serbian Davis Cup hero Viktor Troicki on Monday.

In the women’s singles Victoria Azarenka and Li Na restored order at the French Open after Roland Garros had lost its top two seeds before the fourth round, a 40-year low point for Paris.

Belarusian fourth seed Azarenka, a 2009 quarter-finalist, reached the last 16 with a 6-3, 6-2 win over Italian 30th seed Roberta Vinci while Li, the Chinese sixth seed, enjoyed a comfortable 6-2, 6-2 win over Romania's Sorana Cirstea.

Their wins came a day after top seed Caroline Wozniacki as well as 2010 runner-up Samantha Stosur was knocked out in the last 32 while second seeded Kim Clijsters exited the day before in the second round stage.

It was the first time since 1971 that the top two seeds had failed to get beyond the third round.

The 21-year-old Azarenka, who next faces Ekaterina Makarova of Russia for a place in the quarter-finals, said she still had improvements to make in her game.

That's despite her playing in Paris at a career-high number four in the world and having won back-to-back titles in Miami and Marbella this year.

Li reached the fourth round for the second time and will next face dangerous Czech ninth seed Petra Kvitova who ended American interest in the tournament with a 6-4, 6-2 win over
Vania King.