As most had hoped and everybody had expected, there was no altering the collision course. Rafael Nadal, the nine-time French Open champion, will indeed face Novak Djokovic, the world's indisputable No. 1 player, today in the quarter-finals at Roland Garros.

That heavyweight bout is to be fought on Nadal’s 29th birthday, and the Spaniard, the greatest clay-court player in history, will presumably need to be at or near his very best to celebrate.

Nadal advanced out of the fourth round on Monday with a 6-3, 6-1, 5-7, 6-2 victory over Jack Sock, a young, unseeded American whose power and hustle helped turn a rout into a contest. Nadal faltered after serving for the match at 5-4 in the third set. Djokovic had fewer problems in closing out his 6-1, 6-2, 6-3 victory over Richard Gasquet, the 20th-seeded French veteran.

La Decima

“Now we can talk,” Nadal said, finally addressing the Djokovic match after refusing to look ahead earlier in the tournament. “It’s probably the toughest quarter-final in my career here at Roland Garros, without a doubt.”

It is, quite possibly, the highest-profile men’s quarter-final of the Open era. Nadal is on the quest for “La Decima” – a 10th title in Paris. Djokovic is trying to win the only Grand Slam singles title he lacks, having been thwarted here six times by Nadal in the past decade.

The only recent quarter-final with this kind of heft was the 2001 duel between Pete Sampras and Andre Agassi, at the US Open. That produced one of their finest matches, won by Sampras after four tiebreakers.

But both of those superstars had already won in New York. Today’s match has more at stake and could also represent the end of a remarkable era of dominance for Nadal, who is 70-1 at the French Open but has lost five matches on clay, his favourite surface, this year. That is more defeats than he had on clay from 2006 to 2010.

His downbeat season, full of out-of-character mishits and abrupt dips in form, explains why he is seeded only No. 6.

“It does feel different, because it’s quarter-finals,” Djokovic said. “I’m not used to playing him that early. But you know, that’s the reality, and that’s a challenge that both of us have to accept . . .

“Playing him here and playing him in any other tournament in the world is completely different. Conditions are very suitable to his style.”

The other quarter-final in the top half of the draw will match Andy Murray against David Ferrer of Spain. Murray, undefeated on clay this season, beat Jeremy Chardy of France, 6-4, 3-6, 6-3, 6-2, on Monday. Ferrer, a finalist here in 2013, defeated Marin Cilic of Croatia, 6-2, 6-2, 6-4.

For now, however, nearly all eyes will be on Nadal-Djokovic, which feels like a summit meeting that has been shifted unexpectedly to base camp. Nadal leads their series by 23-20.

They have not played each other in a quarter-final since 2007 in Rome, and their last three matches at Roland Garros were in the 2012 final, the 2013 semi-final and the 2014 final – all won by Nadal.

Fair point

“You can write what you want if it sells, but this is not the match of the year,” Nadal said. “Matches of the year are finals, decisive matches.”

Nadal makes a fair point. Winning today is no free pass to the trophy, and if it turns into one of their ultramarathons – like their 5-hour-53-minute tussle in the 2012 Australian Open – it could definitely sap the winner's strength for future games.

“I’d be very surprised if this is not a tight match,” said Paul Annacone, who has coached Sampras and Federer. “Before the tournament started, I favoured Novak, and I still do. But I still think the hardest thing in men’s tennis is to beat Rafa three out of five sets on clay.”

For now, Nadal-Djokovic in Paris is undoubtedly the matchup of the year, at least until one of the Big Four has to try to stop Djokovic from completing a calendar-year Grand Slam – if he somehow gets that far.

The pressure would seem heavier on Djokovic, who is both the favourite based on his 2015 form and the man without a title here. But he is accustomed to bearing that burden.

“Of course, it is a different approach, mentally, when you play Nadal in quarter-finals than any other player,” he said.

“There’s no doubt about that. I’m going to try to keep my routine the same and not give so much importance to the match. I don’t want to spend too much energy before getting on the court, because I know that for me it’s necessary to have every source of strength and energy possible. I know what to do.”

The thrilling thing is that Nadal does, too. “He’s got to keep the ball deep, and keep the margins good,” Annacone said.

"He can't play short too often. He's got to use his forehand up the line to back Novak up, and just have to play like the Rafa of old. If he does that, he's got a really good chance, and if he doesn't, he won't win." New York Times Service