Djokovic seemed unsure how to trouble the Italian.

He tilted his head back in frustration when, in the second game of the second set, his attempted drop shot landed short. Then, his lob was not quite high enough and Sinner smashed it easily. Finally, when a 26-stroke rally went his way — featuring sliced drop shots and even improbable retrieves — Djokovic got a huge ovation from the crowd, who bellowed out “Novak! Novak!” as he milked their applause. That made it deuce. But Sinner took the game.

Sinner was becoming the Roland-Garros showman Djokovic so often was on the main court, where he won three of his major titles.

One improvised flick-of-the-wrist drop shot from back of the court was majestic, too good even for Djokovic to get back.

Djokovic had a brief massage on his upper right thigh during the changeover at 6-5 down. Serving for the second set for a second time, Sinner clinched it when Djokovic could not return his strong serve.

Djokovic took a medical time out immediately and received massage treatment on the same leg for a few minutes.

He looked sharper in the third set, but Sinner held his nerve.

What was wrong with Musetti?

Earlier, Musetti was struggling with his left leg.

He was 5-0 down after 16 minutes of the third set when he called for a trainer. Alcaraz broke Musetti in the next game to clinch the set in 21 minutes, winning 24 of 29 points.

“It’s not great to win a match like this. Lorenzo is a great player,” Alcaraz said. “I wish him all the best.”

Musetti called for the trainer again after the third set and, after Alcaraz broke his serve to lead 2-0, Musetti walked slowly up to the net and received a hug from Alcaraz.

“I felt at the beginning of the third when I was serving, I start losing a little bit of strength on the left leg behind,” Musetti said. “Tomorrow I will do exams.”