"He was serving extremely well," Sinner said. "You have to use your small chances well."

Auger-Aliassime is one of the most consistent indoors players, but he was unable to trouble Sinner in a one-sided contest that saw the Italian at his clinical best as he won his fifth title of the year and 23rd of his career.

Sinner won on his first match point with a crisp two-handed backhand down the line, tilted his head back and raised his arms. He then patted his heart as he waved his racket to the crowd.

"The past couple of months have been amazing. We have tried to work on things, I've been trying to improve as a player, and getting this kind of result makes me extremely happy," Sinner said.

"It has been an amazing year no matter what comes in Turin."

Although Auger-Aliassime had more aces — eight compared to his opponent's six — Sinner won 91 percent of first-serve points compared to Auger-Aliassime's 81 percent.

"Everything was on the quality of his serve," Auger-Aliassime said. "Hats off to him."

Auger-Aliassime, who has won titles this year in Adelaide, Montpellier and Brussels, received a time violation warning from chair umpire Nacho Forcadell when serving at 30-30 in the ninth game of the second set.

At the changeover, Auger-Aliassime stood and questioned Forcadell, who told him he should have been ready.

Auger-Aliassime disagreed.

"I was ready to receive the balls, I didn't have the balls (from the ball kids)," he said. "If I don't have the balls, how can I get ready to serve? I didn't have one ball in my hand."

Auger-Aliassime then sat down and muttered to Forcadell: "You're not serious. You're really not serious, you're really, really not serious."

Sinner served out the first set, clinching it with a whipped forehand winner at the net when his opponent's drop shot sat up invitingly.

There was a brief glimpse of hope for Auger-Aliassime when he was 5-4 up and took Sinner to deuce on his serve in the 10th game.