Novak Djokovic advanced to the semi-finals of the ATP Finals on Thursday night after Jannik Sinner beat Holger Rune, keeping alive the Serb's bid for a record-extending seventh title at the season-ending tournament.
Sinner was already assured of a spot in the last four following Djokovic's earlier victory over reserve Hubert Hurkacz – the Pole was drafted in to replace the injured Stefanos Tsitsipas – and the world No 4 topped the group after a battling win at the Pala Alpitour in Turin.
"It was hard, I'd never beaten him before... the crowd helped me a lot," said Sinner, who became the first-ever Italian to progress from the ATP Finals group stage. "I'm pleased with how I won the game."
With Sinner already assured of a semi-final berth, the Italian could have lost against Rune knowing that a defeat would eliminate Djokovic from the tournament.
But Sinner fought hard to secure first place with his third win in three group matches, allowing world No 1 Djokovic to follow him into the next round.
In the semi-finals, the reigning Toronto Masters champion will play whoever finishes second in the Red Group, while Djokovic will face the group winner.
Carlos Alcaraz and current Red Group leader Daniil Medvedev, who is also already in the semis, face off on Friday afternoon before Alexander Zverev takes on eliminated Andrey Rublev.
Sinner initially looked like making short work of Rune despite the Dane only having to play three games in his previous match with Tsitsipas on Tuesday before the Greek dropped out of the tournament injured.
The 22-year-old Italian came through a three-hour thriller against Djokovic but looked ready to take on the world when he broke Rune twice in the first three games.
Fatigue and a back niggle allowed Rune back into the match, but Sinner held firm to bask in the cheers of fans who chanted his name to the rafters.
"My back is OK, I felt a small pain but it's gone now," Sinner said. "It might have just been the tension of the match, I didn't even call over my physio. I'm not worried."
Sinner's win saved Djokovic from a disappointing end to what has been an age-defying 2023 from the 36-year-old, who won three Grand Slams and took his 1000 Masters titles to 40, another record.
Djokovic took control at the end of the first set of his match with Poland's Hurkacz when he rattled off nine points in a row to take a 6-0 lead in the tie-break and then seal the set.
However, he threw away his serve to love in game five of the second set and two games later looked on in disbelief as Hurkacz rammed home four consecutive aces from 15-40 down to go to within one game of drawing level.
Hurkacz easily saw out the set, drawing warm applause from the home crowd, and with the third set almost irrelevant the Pole collapsed against a visibly annoyed Djokovic, whose hopes of a historic win are still alive.