PARIS — Only two men have defeated Rafael Nadal on the clay of Roland Garros, where the 11-time French Open champion boasts a 91-2 record.

Roger Federer is not one of them.

Friday, the Swiss champion will try to check one of the few unchecked boxes on the most impressive résumé in men’s tennis when he and Nadal resume a rivalry, now 15 years old, that has demanded the best from each.

Their French Open semifinal Friday, set up by Nadal’s 6-1, 6-1, 6-3 victory over Japan’s Kei Nishikori on Tuesday, followed by Federer’s trickier 7-6 (7-4), 4-6, 7-6 (7-5), 6-4 defeat of Swiss countryman Stan Wawrinka, will mark the 39th meeting in their careers.

Nadal, who turned 33 this week, holds a 23-15 edge. But Federer, two months shy of his 38th birthday, has won their past six meetings — albeit not on clay since 2009, when the Swiss beat Nadal in Madrid.

“We shared the most important moments of our careers together on court facing each other,” Nadal noted, “so [it] is another episode of this, and [I am] happy for that and excited, no? Will be special moment.”

Their first French Open meeting was a highly anticipated semifinal in 2005.

Both had the hallmarks of greatness then. They also had intoxicating, contrasting games and styles.

Nadal was a teenage pirate in Capri pants and sleeveless shirt, with limited English and a lot of “Vamos!”

Federer, clad in white, evoked an artist on break from his atelier. And on court, he moved with a dancer’s grace and lightness.

They proceeded to build one of the greatest rivalries in sports, with the hegemony shifting, more or less, according to the surface.

But between them, always respect.

That Nadal and Federer arrived at the 2019 French Open’s semifinal should not have been stunning. As the tournament’s No. 2 and 3 seeds, they were placed in the same half of the 128-player draw. Yet it was, spiking demand for Friday’s long sold-out tickets.

(Friday’s other semifinal will pit top-ranked Novak Djokovic of Serbia or No. 5 seed Alexander Zverev of Germany against either No. 4 seed Dominic Thiem of Austria or 10th-seed Karen Khachanov of Russia.)

Federer had not competed at the French Open since 2015. He was sidelined by injury in 2016, then skipped the two-week slog on clay in 2017 and 2018 to channel his energy and focus on his grass-court preparation for Wimbledon, where he has won eight of his men’s record 20 Grand Slam tournaments.

Warmly embraced upon his return to Roland Garros last week, Federer explained that he did so because “it felt right.” But he acknowledged that he had no idea and few expectations for how he would fare.

Nonetheless, the Swiss has been close to perfection from the outset, as has Nadal, dominating their respective five matches in the run-up to Friday’s meeting.

More importantly, they have won efficiently, each dropping only one set en route: Nadal to David Goffin in the third round; Federer to Wawrinka, his Olympic and Davis Cup doubles partner, whose game he knows intimately.

Nadal and Federer have spent almost identical time on court to reach the tournament’s final four: 10 hours 59 minutes for Nadal; 10:45 for Federer.

The 34-year-old Wawrinka expended nearly half that (5:09) in his five-set triumph over Stefanos Tsitsipas just 48 hours before he stepped onto Court Suzanne Lenglen to take on Federer. So it was impressive that Wawrinka, who was knocked from the top 200 by knee surgery a year ago, was as sharp and energetic as he was.

With his shot-making and tenacity, Wawrinka forced Federer to tap his full array of shots and attack more than customary.

Apart from the longed-for semifinal date with Nadal, Federer had extra motivation. Wawrinka is the last man to have beaten him at the French Open, in 2015.

After two decades on the pro tour, Federer has a well-established routine for preparing for matches. But when the opponent is Nadal, he confessed, it requires something extra, particularly to handle the left-handed Spaniard’s devilish spin.

“If you want to do or achieve something on the clay, inevitably, at some stage, you will go through Rafa,” Federer said, “because he’s that strong, and he will be there.”

On Friday, so, too, will Federer.