Top seed Novak Djokovic advanced to the semi-finals of the US Open when Frenchman Jo-Wilfried Tsonga retired at the start of the third set of their quarter-final trailing 6-3 6-2.
Tsonga took a medical timeout during the changeover at 5-2 of the second set and had the area below his left knee taped.
World No.1 Djokovic held serve at love to close out the set for a 6-3 6-2 lead but the Frenchman walked off to give the Serbian passage into the last four for the 10th consecutive time.
It has been a strange slam for Djokovic, who has played only two full matches in the tournament, gifted by a walkover in the second round and a retirement after six games in the third round before his abbreviated match with Tsonga.
Djokovic advanced to a semi-final against France’s 10th seed Gael Monfils, who beat compatriot Lucas Pouille in straight sets. Monfils has yet to beat Djokovic in 12 career meetings.
Monfils overwhelmed worn-out compatriot Lucas Pouille 6-4 6-3 6-3 to become the first man into the semi-finals.
Tenth seed Monfils was his dynamic self and invincible from the service line in a commanding win over 22-year-old Pouille, who was coming off three successive five-set wins including a fourth-round upset of 14-times grand slam winner Rafa Nadal.
Monfils finished 24th seed Pouille with his 13th ace to lead off a huge day for the French, who placed three men in the quarter-finals of a grand slam for the first time since the 1947 French Open.
“I’m happy with my performance. I think it is never easy to play quarter-final against a French guy, you know,” Monfils told reporters after the two-hour match. “I think I handled it pretty good mentally and tennistically.”
Monfils, 30, said he regards Djokovic as one of the greatest players ever, but would not shrink from a chance to play the Serb for a berth in Sunday’s final.
“He’s a better player than me, definitely. I think I have no shame to say it. He is better than me,” said Monfils, before suggesting that a breakthrough was possible on any given day.
“You can be the best, but one match is enough, you know. If I face him, I will take the one match as enough.”