The most complete player in tennis and the sport's hottest newcomer come face to face on Friday when Roger Federer and Rafael Nadal slug it out for a place in the French Open final.
What would have been a dream title match comes one round too soon and the winner will be overwhelming favourite to claim his first Roland Garros trophy.
Twelfth seed Nikolay Davydenko of Russia meets unseeded Argentine Mariano Puerta in the other semi-final.
Victory on Sunday would make Federer the sixth player in history to win all four Grand Slams, an astonishing achievement for a 23-year-old who won his first major title at Wimbledon in 2003.
"That would be definitely a dream come true," Federer said.
Nadal, who turns 19 on Friday, is bidding to become the first man to win the French Open on debut since Sweden's Mats Wilander in 1982.
The burly Spaniard has destroyed everything standing in his way to the last four and has already won five titles this year.
The left-hander with the devastating forehand has been described by John McEnroe as the most exciting newcomer since Boris Becker triumphed at Wimbledon for the first time 20 years ago.
ASTONISHING WINNERS
Not only can Nadal fire astonishing winners from all corners of the court but he also seems strong enough physically and mentally to wear down any opposition.
Federer, however, is a different proposition from anyone else on the men's tour.
The Swiss top seed has not dropped a set nor lost his cool in the tournament. He is the perfect combination of elegance and power. He is master of every shot in the book and can do damage on any surface.
Strangely, he has struggled here, a quarter-final appearance in 2001 being his best result until this year.
The pair are tied 1-1 but have never met on clay. In the Miami final this year on hardcourt Nadal won the first two sets before Federer fought back to win 6-1 in the fifth.
"It's going to be really interesting to see," Federer said. "For me it's a big moment. It's one of those chances to walk away with the title here."
Nadal, who is on a 22-match winning streak on clay, is happy to be considered the underdog.
"He is the favourite, no?," said the young Spaniard, whose English is not as impressive as his on-court fist-pumping.
"He has the pressure. He is the number one."
