“Seeing Novak (injured) is, for everyone, disappointing,” Sinner said, “so I wish him a speedy recovery.”

Amid a season in which Djokovic is only 18-6 and has not reached a final at any tournament, let alone won one, he needed to get back to the title match at the French Open to continue to add to his record for most weeks at No. 1.

For years and years, Djokovic, Nadal and Roger Federer ruled men’s tennis as the so-called Big Three, accumulating a total of 66 major championships among them. But Federer, now 42, is retired, and Nadal, who turned 38 on Monday, is trying to figure out how much longer he can compete after missing most of the past 1 1/2 seasons with injuries.

No one knows yet how long Djokovic, 37, will be sidelined or what, if any, effect this might have on his future.

Wimbledon, where has won seven titles, starts July 1, and the tennis competition at the Paris Olympics starts at Roland Garros on July 27.

“I saw that he was obviously physically struggling (Monday), and I honestly thought … he was on the verge of losing,” said U.S. Open champion Coco Gauff, who made her way into the women’s semifinals with a three-set win over Ons Jabeur and will play No. 1 Iga Swiatek on Thursday.

Seeing Djokovic pull out the win against Cerundolo, Gauff said, made her think “that he would win the title.”