PHOTOS: Federer, Djokovic rally into French Open semis

Novak Djokovic came back from the brink to save four match points before he downed local favourite Jo-Wilfried Tsonga 6-1, 5-7, 5-7, 7-6, 6-1 in the French Open quarter-finals and keep alive his dream of holding all four Grand Slam titles on Tuesday.

Serbian world number one Djokovic, looking to become the first man in 43 years to win the four majors consecutively, kept cool under tremendous pressure to save four match points on his serve in the fourth set, forcing a tiebreak he won 8-6 before breaking decisively early in the fifth.

Djokovic, who will join American Don Budge and Australian Rod Laver in the club of players having held all four major titles at once if he lifts the Musketeers Cup, will now take on third seed Roger Federer in a re-match of last year's epic semi-final won by the Swiss.

Roger Federer withstood two sets of Argentine fireworks before dousing Juan Martin del Potro's challenge with a 3-6, 6-7, 6-2, 6-0, 6-3 win on Tuesday to reach the semi-finals of the French Open. 

The Swiss third seed's chances of winning a second title here appeared to be sinking fast as he drowned under a hail of winners flying off Del Potro's racket in the opening two sets.

But the 2009 champion stayed calm to break for a 2-0 lead in the third set and from then on Del Potro's dodgy left knee and mindset started to let him down.

The ninth seed won only eight points during a forgettable fourth set and his misery was compounded when he bowed out after a forehand clipped the net and bounced out to hand Federer victory.

Federer, looking for a record 17th Grand Slam crown, next faces Novak Djokovic or Jo-Wilfried Tsonga for a place in Sunday's final.

Australian sixth seed Samantha Stosur reached the semi-finals of the French Open for the third time in four years when she outfoxed Slovakian 15th seed Dominika Cibulkova 6-4, 6-1 on Tuesday.

The U.S. Open champion, who will face either Italian Sara Errani or German Angelique Kerber for a place in Saturday's final, advanced into the last four without dropping a set.

Stosur, who reached the semi-final in 2009 and the final in 2010 in the claycourt Grand Slam, prevailed on composure and tactical finesse, using her kick serve to stave off nine of 10 break points.

She struggled at first with her opponent's power but Cibulkova collapsed after losing the opening set, with Stosur winning six games in succession to wrap it up after 85 minutes.

Italy's Sara Errani showed no signs of ending her giant-killing run at the French Open as she cut 10th seed Angelique Kerber down to size with a 6-3, 7-6 win to reach her first Grand Slam semi-final.

Errani had already dumped out former champions Ana Ivanovic and Svetlana Kuznetsova in the two previous rounds and she proved that those wins were no fluke as she recorded her first victory over a top 10 player following 28 failed attempts.

Left-hander Kerber had been bidding to become the first German woman to reach the semis since Steffi Graf in 1999 but she was outwitted and out-punched by the 21st seed.

Errani ended a scrappy second set, which featured six successive breaks and eight in total, with an unreturnable serve to book a semi-final date with 2010 runner-up Samantha Stosur.