The most eagerly-awaited clash of the tournament pitches Nadal, on a 22-match winning streak, against the world number one who is bidding to become just the sixth man in history to win all four Grand Slam tournaments.

The muscular Nadal has his sights set on being the first man since Mats Wilander in 1982 to win the French Open on his debut.

Such has been the anticipation that the second semifinal between Russian 12th seed Nikolay Davydenko and unseeded Argentinian Mariano Puerta has been completely overshadowed.

Puerta feels he has a point to prove having served a nine-month drug suspension while Davydenko, 24 on Thursday, aims to show there's more to Russian tennis than a handful of glamorous blondes on the women's circuit, and the mercurial Marat Safin on the men's.

"Federer has all the pressure," insists Nadal.

"He is the number one. I will try and play my best tennis to win and I think I can win if I play my best. He is playing really well and I know it's going to be a complicated match."

Nadal has been the sensation of 2005 winning five clay-court titles including back-to-back Masters in Monte Carlo and Rome.

That figure could have been three.

At the Miami Masters in March, Nadal was within two points of beating Federer in the final before the Swiss top seed mounted a stunning fightback to win a five-set thriller.

In 2004, Nadal had beaten his rival at the same event.

"That was on hard courts, this is clay. It's going to be different. I have been playing well so far," said Nadal who has been trying to play down the significance of the semi-final duel.

"I don't want to think about this as being the biggest match of my life because I don't want to put pressure on myself. But it is a wonderful match and an important match.

"This is very good for my career. A final at 19 would be unbelievable as my objective was to make the semi-finals here."

Of the two, Nadal has had the more testing path to the last four having to beat French teenager Richard Gasquet, one of just two men to have defeated Federer in 2005, in the third round.

He then put out another home favourite Sebastien Grosjean dropping a set for the first and only time before easing past compatriot David Ferrer in the quarterfinals.

Federer has yet to drop a set so far and comfortably overcame his sternest test against 1998 champion Carlos Moya in the fourth round, though the Spanish former world number one was suffering from a sore shoulder.

He has reached the semi-finals here for the first time after enduring three miserable years where he failed to get beyond the third round.

"It's purely the experience, the big matches, the occasions I have faced. Overall I believe in my game more, not just my clay court game but my all of my game," said 23-year-old Federer who has already collected six titles in 2005 and has been beaten just twice.

"We're not quite there yet. But to win the French Open would be a dream come true. It would mean I have won all the Grand Slams. At 23, that would be quite something.

"For me it's a big moment. There are still two matches to go but it's one of those chances to maybe walk away with the title."

The winner of the tie will face either Davydenko or Puerta, both of whom battled through marathon quarterfinal five-setters, for a place in Sunday's final.

The 26-year-old Puerta was sanctioned in October 2003 for testing positive for clenbutherol in Vina del Mar, Chile.