Carlos Alcaraz claimed an opening victory at the ATP Finals for the first time, beating Alex De Minaur in straight sets.
The top seed is making his third appearance at the end-of-season showpiece in Turin having reached the semi-finals on his debut in 2023 before falling at the group stage last year.
On both occasions, Alcaraz was beaten in his first match, but he put that right this time with a 7-6 (5) 6-2 victory over seventh seed De Minaur.
The young Spaniard made a flying start and looked set for an easy first set when he led 4-1 40-0, but De Minaur fought back and led 5-3 in the tie-break only for Alcaraz to win four points in a row.
In the second set, Alcaraz maintained his lead to get his quest for a first ATP Tour title and the year-ending world number one ranking off to the perfect start.
"I've been struggling in the past few years to come to the end of the year with motivation," said Alcaraz on atptour.com.
"This year is a little bit different, which I’m proud about. I’m doing the right things to give myself a shot to try and win this tournament."
There was also an opening victory for third seed Alexander Zverev, who saved three set points in the second set to secure a 6-3 7-6 (6) win against debutant Ben Shelton.
Zverev looked to have the match under control until the second-set tie-break, when big-serving Shelton led 4-0 and 6-3, but the American could not push the contest to a decider.
There was a big reaction from Zverev after he secured the straight-sets win, with the German bidding for a third title at the event.
British doubles pair Julian Cash and Lloyd Glasspool have work to do if they are to reach the knockout stages on their first ATP Tour Finals appearance together after the top seeds lost 7-5 6-3 to home duo Simone Bolelli and Andrea Vavassori.
