Carlos Alcaraz loses to Alexander Zverev in his ATP Finals debut; Daniil Medvedev soundly beats good friend Andrey Rublev

TURIN, Italy (AP) — Considering all that he's accomplished over the last two years—two Grand Slam titles and finishing last season as No. 1—Carlos Alcaraz no doubt belongs among the world’s elite.

Still, this wouldn't have been the ATP Finals debut the 20-year-old Spaniard was hoping for at the season-ending event for the year's top eight players.

After missing the finals last year because of an abdominal injury, Alcaraz was beaten in his opening match on Monday by two-time champion Alexander Zverev 6-7 (3), 6-3, 6-4.

In the other red group match, Daniil Medvedev quickly dispatched his good friend Andrey Rublev 6-4, 6-2.

Zverev also missed last year's edition after tearing ligaments in his right ankle in the French Open semifinals. But the big-serving German clearly likes the fast conditions inside the Pala Alpitour, where he claimed the title two years ago.

Zverev served 16 aces to Alcaraz's 11, saved five of six break points, and never really let Alcaraz feel in control.

"I had a few break points that I couldn't take, and I think that was the key of the match," Alcaraz said.

Added Zverev, "I served very well. That helped."

Zverev overcame a scare late in the third set when he was chasing down a forehand from Alcaraz, lost his grip, slipped and fell to the court clutching his left ankle. But Zverev quickly shook it off and held in that game for a 4-2 lead.

"I didn't twist my ankle. I just kind of slipped. And kind of maybe pinched my Achilles, my capsule a little bit," Zverev said. "Hopefully it's nothing too major and I can continue playing."

Zverev faced a break point while serving for the match and responded with an ace down the middle. Two points later, the match was over.

Zverev has also had off-court issues recently after a German court issued a penalty order against him after allegations he caused bodily harm to a woman. Zverev has disputed the allegations and is contesting the penalty order.

Alcaraz had trouble adjusting to the court's speed.

"This surface is the fastest on the year, that's for sure," Alcaraz said. "I don't know why they put this kind of surface at the end of the year because all the tournaments that we have played on hard court is so, so slow. Then we come here to the Masters and they put this court so fast."

Zverev suggested a slight bit of altitude is a factor, with Turin at an elevation of 784 feet (239 meters), "But generally speaking, the conditions here are very fast," Zverev said.

Still, Alcaraz enjoyed the experience of the fancy lighting and and the tunnel leading out to the court.

"The best walk-out that I've ever done," the Spaniard said. "It was unbelievable experience for me to play my first match ... even if I lost."

Alcaraz can still hope to advance from the round-robin, with the top two finishers in each four-man group reaching the semifinals.

OVERPOWERING MEDVEDEV

Medvedev cranked out 10 aces to Rublev's two to improve to 7-2 in his career against Rublev, who is the godfather of his one-year-old daughter.

Medvedev, who won this tournament in 2020 when it was in London, also reached the 2021 final in Turin.

Rublev beat Medvedev in a third-set tiebreaker in the opening round-robin match a year ago.

Medvedev was so overpowering on Monday that Rublev fell to the ground while at the net late in the second set as he attempted to fend off his friend's heavy groundstrokes—then covered his face with his hands in despair.

Novak Djokovic and Jannik Sinner won their opening matches in the green group on Sunday.