It was just about 300 yards apart on the two main show courts of Roland Garros, where Roger Federer and Novak Djokovic found themselves saving match points at the same time.

Djokovic kept alive his Grand Slam hopes by saving four match points against Jo-Wilfried Tsonga before pulling off a nail-biting 6-1, 5-7, 5-7, 7-6(6), 6-1 quarterfinal win.

In the last four Djokovic will play against Roger Federer on Friday, who bounced back from a two-set deficit to beat Juan-Martin del Potro 3-6, 6-7(4), 6-2, 6-0, 6-3.

Last year in Paris saw the Serb and Swiss stars duel, when Federer ended Djokovic's 43-match winning streak.

Since then, Djokovic has won 26 Grand Slam matches in a row. After his triumphs at Wimbledon and U.S. Open last year, and Australian Open in January, the world No. 1 is bidding to be only the third man, after Rod Laver in 1969, to hold all majors at the same time.

Federer victory over del Potro meant he reached a record-equalling 31st Grand Slam semifinal.

At one stage in Tuesday's quarterfinal it looked like both were on their way out. Federer was two sets to love down against del Potro and Tsonga let four match points slip against Djokovic in the fourth set.

But, in staying true to their superstar status, both found a way back, kept their cool and each won in five sets.

The defeat meant Tsonga's dream of becoming the first Frenchman to win at Roland Garros since Yannick Noah in 1983 had been shattered.It also sets up the 26th encounter between Federer and Djokovic. The former leads their head-to-heads 14-11, but the recent outcomes between the two favours the later.

Djokovic lost in four sets to Federer in last year's French Open semifinals, but that was his only defeat in their last six encounters.

Both men know if they make it to the final, even a greater challenge is waiting for them on Sunday, where the likely opponent is Rafael Nadal who has lost a meager 19 games so far and has yet to drop a set.

Neither of them has ever beaten Nadal at French Open, with the Spaniard now having a career record of 49 wins at Roland Garros and just one loss to Robin Soderling in the fourth round in 2009.

Djokovic took control of the match early on breaking in the fourth and sixth games to pocket the first set in under 21 minutes and then moved 2-0 up in the second as the sun clouded over.

Boosted by the crowd support, the Frenchman broke Djokovic to level at 4-4, and top seed suddenly found himself under big pressure on serve at 5-6 and 15-40 down.

Though he saved the two set points to get to deuce, but eventually hit long to give Tsonga the set.

Djokovic again broke early in the third to go 2-1 up but a series of unforced errors allowed Tsonga to level at 2-2.

Once again a tie-break loomed and once again the fifth seed gave himself a two sets to one lead.

The fourth set eventually turned into a tie-break after Tsonga had four match points, when Djokovic was serving at 4-5, and again on the Serb's serve at 5-6.

The top seed showed his class forced a last set, which was easily captured by him at Court Philippe Chatrier.

Del Potro had looked on course for a straight sets win after unleashing a brutal wave of power-hitting in the first two sets.

However with his left knee heavily strapped, del Potro could not manage to handle Federer, the 16-time Grand Slam title winner and 2009 champion in Paris, in last three sets at Suzanne Lenglen court.