This was their fourth meeting since August, and just eight days after their previous encounter, with the result remaining the same as Sinner gradually took control before overpowering Auger-Aliassime, who required medical treatment during the second set.

Sinner extended his remarkable winning streak on indoor hard courts to 27 matches, his last loss on this surface being against Novak Djokovic in the 2023 ATP Finals final.

The Italian is also competing with Carlos Alcaraz for the year-end world number one ranking. Sinner must defend his title in Turin to keep his hopes alive, while the Spaniard can clinch the top spot by winning two more matches following his opening victory.

Sinner started strongly by taking the first game without losing a point and conceded only three points on his serve in the first set, creating five break opportunities with a sharp combination of backhand and forehand winners down the line.

Auger-Aliassime stayed competitive, hitting eight aces compared to Sinner’s one in the first set, often at crucial moments as he saved four break points, but the Italian prevailed when it counted, breaking serve to take the set.

“It was a very challenging match until 6-5. I had some chances to break,” Sinner commented.

“He played aggressively, so I’m pleased to have overcome a tough test today. Winning the first match is crucial in this tournament and format.”

Sinner surged to a 3-0 lead in the second set, and Auger-Aliassime took a medical timeout due to an issue with his left calf.

“I hope it’s nothing too serious,” Sinner said.

“I wish him a speedy recovery and hope he returns to full fitness soon.”

Auger-Aliassime managed to save two break points to stay in the match briefly before Sinner broke again, putting himself in position to serve for the match, which he closed out emphatically with an ace.

While the Canadian struggled in the second set, Sinner began to enjoy the contest, executing delicate drop shots that thrilled the home crowd, who enthusiastically applauded his win.

On Sunday, German Alexander Zverev defeated American Ben Shelton 6-3, 7-6(6) in the other Bjorn Borg group match. All four players in this group will face each other, with the top two advancing to the semi-finals.

Tuesday’s matches feature the Jimmy Connors Group, where Alcaraz faces last year’s finalist, Taylor Fritz, both holding one win each, while Italian Lorenzo Musetti takes on Australian Alex de Minaur.