TURIN, Italy (AFP) — Carlos Alcaraz made a solid start to the ATP Finals on Sunday with a 7-6 (7/5), 6-2 win over Alex de Minaur, while former champion Alexander Zverev got underway with a straight-sets win over Ben Shelton.

It was the first time that the Spaniard had won his opening match at the finals. He lost to Zverev and Casper Ruud in the last two years.

"This tournament is one of the best tournaments we have on tour," world No. 2 Alcaraz said.

"I've been struggling in the past few years to come to the end of the year with motivation. This year is a little bit different, which I'm proud about (as) I'm doing the right things to give myself a shot to try and win this tournament."

It was not all plain sailing in Turin. Leading 4-1 and pressing for 5-1 in the first set, Alcaraz suffered a sudden dip, struggling with his first serves and allowing seventh seed De Minaur to come back to level the score.

Trailing 3-1 and then 5-3 in the tiebreak, Alcaraz rediscovered his touch to level and then break De Minaur to win the first set.

In spite of dropping his service early, the second set was more straightforward as Alcaraz raced away to claim his fifth victory in as many meetings with the Australian.

"It was a really difficult match," Alcaraz said.

"On this surface, Alex makes the most of the speed of the ball, he's super fast and really difficult on return.”

"I'm just really happy to get through this really difficult challenge, and happy with how I'm playing."

Alcaraz and De Minaur are in the Jimmy Connors Group which also features American sixth seed Taylor Fritz and Italy's Lorenzo Musetti, a late replacement for the injured Novak Djokovic of Serbia.

Later Sunday, third seed Zverev downed Shelton 6-3, 7-6 (8/6) in the first match of the Bjorn Borg Group, which also includes Italian top seed Jannik Sinner and Canada's Felix Auger-Aliassime.

In a meeting between two of the biggest servers in the sport, Zverev broke the American fifth seed twice in the opener to edge ahead after less than half-an-hour on court.

The second set then rumbled inevitably towards a tie-break with few break opportunities appearing for either player.

The 2018 and 2021 winner started the breaker sluggishly as Shelton soon brought himself up three set points at 6-3.

But Zverev started the fightback with a superb backhand passing shot, before sealing match point at the first time of asking as Shelton hit long at the end of a lengthy rally.

"In the tie-break, he started off amazing," Zverev said.

"I felt like I had to control the things that I could control.”

"I did that well at the end of the tie-break and I'm super happy with that win."