PARIS, France (AFP) — Novak Djokovic and Carlos Alcaraz overcame crushing humidity to stay on course for an Olympic final showdown as Rafael Nadal played possibly his final match at Roland Garros.

Djokovic, seeking a first Olympic title, defeated German left-hander Dominik Koepfer 7-5, 6-3, becoming the first man to reach four singles quarterfinals at the Games.

Alcaraz brushed aside Roman Safiullin, the Russian playing in Paris as a neutral, 6-4, 6-2.

Nadal, who has won 14 of his 22 Grand Slam titles at Roland Garros, exited Paris after he and Alcaraz were defeated in the men’s doubles, going down 6-2, 6-4 to US pair Austin Krajicek and Rajeev Ram.

The 38-year-old Nadal, a two-time Olympic gold medalist, walked off Court Philippe Chatrier applauding all four sides of the stadium.

He was later asked whether he had played at Roland Garros for the final time.

“Maybe, I don’t know. If that’s the last time, for me it’s an unforgettable feeling and emotions,” said the injury-plagued former world number one whose ranking has slumped to 161.

In the women’s singles, world No. 1 Iga Swiatek overcame being struck in the body by a full-blooded backhand from Danielle Collins before her American rival retired injured in the final set.

Swiatek will face China’s Zheng Qinwen, who ended the career of former world No. 1 and three-time major winner Angelique Kerber.

The 37-year-old Djokovic has only ever collected a bronze at the Olympics, at Beijing 16 years ago, but he was rarely troubled by his 70th-ranked opponent.

“Bringing a medal to Serbia is always a big goal of mine,” said Djokovic, who has won three of his 24 Grand Slam crowns on Paris’ famous red clay.

Djokovic, who breezed past old rival Nadal in the second round, goes on to face 11th-ranked Stefanos Tsitsipas.

Djokovic boasts an 11-2 head-to-head record over Tsitsipas, including a victory from two sets down in the 2021 French Open final.

“I’ve erased it,” said Tsitsipas when asked to recall that heartbreaking defeat.

French Open and Wimbledon champion Alcaraz has also yet to drop a set in Paris and was coasted by 66th-ranked Safiullin in 90 minutes.

“The conditions were really tough with the heat and it was really humid,” Alcaraz said.

Up next for Alcaraz is Tommy Paul, the American he defeated in the Wimbledon quarterfinals.

Russia’s Daniil Medvedev, appearing as a neutral and seeded to face Alcaraz in the semi-finals, was defeated 6-3, 7-6 (7/5) by Felix Auger-Aliassime.

Defending champion Alexander Zverev eased into the last-eight with a 7-5, 6-3 win over Alexei Popyrin.

Four-time French Open winner Swiatek racked up her 25th successive win on the clay courts of Paris but only after being pole-axed by a fierce backhand from Collins in the first game of the deciding set.

Swiatek took evasive action but still struck a painful blow on her upper body. She crouched on the ground, catching her breath before continuing.

Collins immediately crossed to Swiatek’s side of the net to apologize.

Swiatek swept the first set 6-1 before Collins claimed the second set 6-2.

However, Collins retired with an injury trailing 4-1 in the decider.

Collins then exchanged angry words with Swiatek at the net, later accusing the Pole of being “insincere” over her injury.

Swiatek said that when she was hit by Collins, she “couldn’t breathe for some time.”