Carlos Alcaraz and Novak Djokovic stayed on course for a gold-medal clash after both reached the quarter-finals at Roland Garros.

Djokovic was first out on Court Philippe-Chatrier on Wednesday against the German Dominik Koepfer, and defied 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 Olympic Games 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,” Djokovic said. “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 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 the eighth seed, Stefanos Tsitsipas, while Alcaraz will play the 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 the seventh seed, Taylor Fritz, 6-4, 7-5.

Andy Murray may be clinging on but it was the end of the road for another retiring three-time grand slam title winner, with Angelique Kerber enduring a heartbreaking 6-7 (4), 6-4, 7-6 (6) defeat by China’s Zheng Qinwen in the women’s quarter-finals.

Kerber’s run to the last eight in Paris was her best result this year. The 36-year-old had already announced she would retire ­following the Olympics, having returned from ­maternity leave in January.

“I’ve achieved every­thing I dreamed of,” Kerber said.

“I was No 1, won grand slams, won a silver medal in Rio, so what more could you want in the end? I’m proud of everything I’ve achieved in my career, of what I’ve achieved here, what I did on the court.”

Zheng is now guaranteed a shot at a medal, as is Anna ­Karolina Schmiedlova, the most surprising success story here. The 29-year-old is ranked 67 but followed her upset of the Wimbledon finalist Jasmine ­Paolini by taking out the SW19 champion Barbora Krejcikova, 6-4, 6-2.

The Slovakian’s run is causing quite a stir back home and she said: “I still can’t believe that I’m in the semi-finals and the top four players in the world. 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.”

The top seeds Coco Gauff and Jessica Pegula were knocked out of the doubles in the second round, the Americans losing 2-6, 6-4, 10-5 against the Czechs Karolina Muchova and Linda Noskova, but there was better news for Britain’s Katie Boulter and Heather Watson.

The Team GB pair were impressive 6-3, 6-4 winners against the No 6 seeds, ­Brazil’s Beatriz Haddad Maia and Luisa Stefani, and will face Italy’s No 3 seeds, Paolini and Sara Errani in the quarter-finals.