Rafael Nadal, Carlos Alcaraz's Olympic doubles hopes dashed

The Spanish duo have been one of the star attractions of the tennis event at Roland Garros and another packed crowd cheered them on under the roof on Court Philippe Chatrier.

But this time they met their match as Krajicek and Ram, two of the best doubles players in the game, showed their prowess in the format to claim a 6-2 6-4 victory.

Nadal has been tight-lipped about his future but this could be the 14-time French Open champion's farewell to Paris, and the crowd stood to applaud as he waved to all sides of the court before walking off.

Alcaraz stayed on course for a gold-medal clash with Novak Djokovic in singles earlier after both reached the quarter-finals.

Djokovic was first out on Chatrier on Wednesday against German Dominik Koepfer and defied the hot and humid conditions to claim a 7-5 6-3 victory.

The Serbian is the first player in the modern era to reach the quarter-finals in singles at four different Olympics but he is yet to make a final and has only one bronze medal, from Beijing 16 years ago, to show for his efforts.

"Bringing a medal to Serbia is always a big goal of mine, has been since my first Olympic Games in Beijing, where I managed to get my only medal so far," said the Serbian.

"I had actually some really good Olympic Games but that semi-final hurdle was, three out of four times, tough for me to go through."

Alcaraz, meanwhile, became the youngest man since Djokovic in the Chinese capital to reach the last eight, beating Roman Safiullin 6-4 6-2.

Djokovic next faces eighth seed Stefanos Tsitsipas while Alcaraz will play American Tommy Paul in a rematch of their Wimbledon quarter-final.

Italy's Lorenzo Musetti, meanwhile, conjured up a repeat of his SW19 upset by knocking out seventh seed Taylor Fritz 6-4 7-5, while fourth seed Daniil Medvedev was beaten by Canada's Felix Auger-Aliassime but defending champion Alexander Zverev advanced.

Andy Murray may be clinging on but it was the end of the road for another retiring three-time grand slam champion, with Angelique Kerber suffering a heartbreaking 6-7 (4) 6-4 7-6 (6) loss to China's Zheng Qinwen in the quarter-finals of the women's singles.

The German is calling it quits at the age of 36 having returned to the tour earlier this year following the birth of daughter Liana.

Zheng is now guaranteed a shot at a medal, as is Slovakia's Anna-Karolina Schmiedlova, the most surprising success story here.

The 29-year-old is ranked 67th in the world but followed her upset of Wimbledon finalist Jasmine Paolini by taking out SW19 champion Barbora Krejcikova 6-4 6-2.

Schmiedlova's run is causing quite a stir back home, and she said: "I still can't believe that I'm in the semi-finals. The best game of my life is for the Olympics and for my country and for people around me, so it's a big deal. It's amazing."

Far less surprising is the presence in the last four of top seed Iga Swiatek, who made it 25 consecutive wins on the Paris clay, although she was given a test by Danielle Collins before the American pulled out injured trailing 6-1 2-6 4-1.

Top seeds Coco Gauff and Jessica Pegula were knocked out of the women's doubles in the second round, the Americans going down 2-6 6-4 (10/5) to Czech duo Karolina Muchova and Linda Noskova.

READ MORE: Novak Djokovic and Carlos Alcaraz remain on collision course for Olympic final