Turin, Italy — Cheered on by a raucous home crowd, Jannik Sinner recorded his first win over top-ranked Novak Djokovic at the ATP Finals.

Sinner triumphed 7-5, 6-7 (5), 7-6 (2) in a match spanning more than three hours on Tuesday night and into Wednesday morning.

It was the 22-year-old Sinner's first win over Djokovic in four meetings and ended the Serbian player's 19-match winning streak that stretched back to his five-set loss to Carlos Alcaraz in the Wimbledon final.

Sinner sealed the result when he hammered down a smash at the net to send the Turin arena into a frenzy.

The umpire had to tell the fans to be quiet several times as they fervently cheered their idol on and also booed Djokovic several times.

The 36-year-old Djokovic, who normally enjoys huge support in Italy, lapped up the boos and even encouraged the fans to up their hostility toward him.

Sinner, who beat Stefanos Tsitsipas 6-4, 6-4 in Sunday's opener, is now on the verge of reaching Saturday's semifinals. He next plays Holger Rune, who has one win after Tsitsipas retired early in their green group match and withdrew from the tournament.

Djokovic, who is looking to break a tie with Federer and capture a record seventh title at the tour finals, will play first alternate Hubert Hurkacz.

Tsitsipas withdraws

Tsitsipas withdrew with a back injury after playing only three games of his second match in Turin.

Tsitsipas, the 2019 champion, was trailing 2-1 in the opening set when he had a lengthy conversation with his trainer before slowly getting to his feet, shaking his head and walking over to shake Rune's hand.

That was after only 17 minutes of play and led to boos from the crowd in Turin, which instead had to settle for an exhibition match between alternates Taylor Fritz and Hurkacz.

"My apologies to all the fans and the crowd that came to support me today and watch the match. I'm really gutted that I wasn't able to finish the match," Tsitsipas said. "My doctors and the countless visits that I had in the last few days suggested that I play, they gave me the green light to go and try.

"Unfortunately I felt terrible on the court ... I hate retiring from matches, I'm not that kind of person that likes leaving mid-match and it kills me not to be able to finish this tournament, the one that I've prepped for for so long, made sure that I'm completely fit to perform at my best and show my capacities as a player."

Tsitsipas had cut short a practice session on Friday because of an apparent physical issue but the Greek player said he was "absolutely fine."

Rune lost his opener to Djokovic 7-6 (4), 6-7 (1), 6-3.

"For sure (not the way I wanted to win). It is very unfortunate," Rune said. "You could see in the first service game, he was not serving as full as he can.

Tsitsipas also withdrew from the tournament in 2021 after losing his opening match.

"It definitely hurts me a lot because this is the tournament that means the most to me, including the Grand Slams," he said.