TENNIS/French Open: Whatever about the merits of Nikolay Davydenko v Mariano Puerta, in today's semi-finals, the one pairing that has captured hearts and minds at Roland Garros is the hotly anticipated meeting between Roger Federer and Rafael Nadal.

The left-handed Spaniard, 19 years old today and threatening to dominate world tennis against the Swiss 23-year-old, who is already being compared to the great players of the game.

Such high-powered matches serve a number of purposes, not least of all as an indicator for Wimbledon, which follows on just two weeks later. The contest will also illustrate how close Nadal is to the three-time Grand Slam champion in what is a high stakes game for both players.

Federer, by winning here will join that elite band of players who have won a major on all four surfaces, while Nadal seeks a first Grand Slam final in his first French Open effort. The youngster's last outing with Federer was in Miami.

But as he pointed out after his quarter-final against Spain's David Ferrer, this is a different moment and a different surface. Nadal talks with respect about Federer's ability, but also with a fearless confidence about his own. "Each match is different. I hope it is not going to be like Miami because I lost," said Nadal. "Here it is a different surface. We're on clay. It's going to be different and I am going to try and play well, like I've been playing so far, all the clay tournaments, Barcelona, Monte Carlo, the final in Rome."

The fourth seed comes into the match unbeaten in three tournaments. He has the best clay-court record of any player this year, including Federer, and faces him with a 22-match unbeaten run.

Of the 56 sets played in his three-tournament streak, Nadal has lost only seven.

Only Andre Agassi, who won 23 consecutive matches when he was a teenager back in 1988, has a better run of teen victories.

Not that Nadal's accomplishments should overly concern the number one. Federer assembled his own unbeaten record earlier in the year. While Nadal came into Roland Garros on the crest of success, Federer's 25-match streak between February and April of this year is the longest of the season. Nadal has also won a total of five titles, once again just short of Federer's six wins.

"He is the number one," acknowledged Nadal. "He is the favourite, no? I think I can win if I play my best tennis and he doesn't play the best match."

That is how most see it. There's no doubt that Nadal's big game can match that of Federer, but at his best there is simply no one who can soar as high as the favourite.

Davydenko, a rather frail looking player compared to the beefed up Puerta or Nadal turned 24 yesterday and has achieved all he could ever have expected. In that respect, the pressure is off the Russian, who has never travelled so far into a Grand Slam. "Its okay. I'm feeling happy. I've reached the top 10 in ranking," he said after beating Tommy Robredo in a tight five-set quarter-final. Only the sixth Russian to have gotten this deep into a Grand Slam, Davydenko hopes to emulate Marat Safin and Yevgeny Kafelnikov, the only two Russian players to have gone on and claimed Grand Slam titles.

At least he knows what to expect. A committed baseline player, Puerto will plant himself at the back of the court and hit topspin on everything.

That has gotten him further than he has ever been before in a Grand Slam. The only previous occasion that he had even been in the third round of a Major was at Roland Garros in 2000 when he was forced to retire with a hamstring injury.

"If you are good why do you have to be bad here," said Davydenko somewhat rhetorically. "Tennis the same. In some tournaments you beat these guys, so why can't you beat them here."