PARIS // Li Na was pushed to the limit before she sealed a spot in the French Open quarter-finals today but the winning machine Novak Djokovic did not need to hit a ball to take his place in the men's last four.

Australian Open runner-up Li, the first Chinese player to reach the Roland Garros quarters, outlasted the Czech ninth seed Petra Kvitova 2-6, 6-1, 6-3 on another warm day in western Paris but with thunderstorms forecast later.

After a lightning-quick third-round victory over Sorana Cirstea, the sixth seed Li was given a much tougher test but again impressed the tennis connoisseurs on Court Philippe Chatrier with her dogged determination and weight of shot.

She battled back from an early break in the third set to prevail and prompted the suited gentlemen in the galleries to tip their panama hats in appreciation.

Djokovic was already looking almost unstoppable in his bid for a first title in the clay grand slam and now he will get an extra's day rest compared to the others in the men's draw.

His quarter-final opponent has Fabio Fognini pulled out of tomorrow's slated match after failing to recover from a thigh injury sustained in yesterday's long five-set duel against Albert Montanes.

"My doctors said if I play tomorrow maybe it can be dangerous," Fognini said.

Serbia's red-hot second seed Djokovic is on a 41-match winning streak since the start of the year, just one behind John McEnroe's 1984 record.

His progression through the last eight will not count as part of the streak, officials confirmed, so the world No 2 will have to lift the trophy if he is to break the American's mark in Roland Garros. Roger Federer could loom in the semi-finals.

Another player with injury problems is fourth seed Andy Murray, who is due to play Viktor Troicki in the fourth round later if he has sufficiently shrugged off an ankle injury suffered in his easy win over Michael Berrer on Saturday.