Carlos Alcaraz was beaten in three sets by Alexander Zverev on Monday as the world No 2 started his ATP Finals campaign in disappointing fashion.
Alcaraz, making his debut at the season-ending event, took the first set after a tiebreak in Turin but seventh seed Zverev fought back to level the scores before going on to seal a 6-7, 6-3, 6-4 win.
The Spaniard went into the match already knowing there would be no chance of overhauling Novak Djokovic as world No 1 before the end of the year after the Serbian defeated Holger Rune on Sunday.
Alcaraz was knocked out of the Paris Masters by Russian qualifier Roman Safiullin in his first game back from injury having not played since the Shanghai Masters in early October due to lower back and left foot problems.
Two-time winner Zverev is tough opposition on hard courts like the one at the Pala Alpitour and made full use of his height and power to see off Alcaraz in a Red Group that also includes Daniil Medvedev and Andrey Rublev, who face off later on Monday.
“My serve helped me a lot. Saving the break point in the first game of the second set helped me,” Zverev said. “You don't want to go down a set and a break against the world No 2, so I am happy.”
The German – who was champion in 2018 and 2021 – missed last year’s event after suffering a serious right ankle injury during his French Open semi-final against Rafael Nadal at Roland Garros.
And a packed crowd in Italy might have feared the worst when Zverev began to walk gingerly between points after falling on his left ankle.
“I didn't twist my ankle. I kind of slipped. There was a pain for a while and I don't think any damage has been done,” Zverev said of his fall. “I hope not and we will see when it settles down. It is nothing comparable to Paris.”
Alcaraz can still hope to advance from the round-robin format, with the top two finishers in each four-man group reaching the semi-finals.
Before Zverev's win, Djokovic was presented with the trophy for finishing the season as top-ranked player, a position he secured after winning his thrilling Green Group opener with Rune in a match that lasted more than three hours.
Djokovic is red-hot favourite to claim his seventh Finals title, which would put him out on his own as the record winner, one ahead of retired great and old rival Roger Federer.
“It's obviously the crown of the season, finishing the year as number one in the world I think is a dream of every tennis player, it's one of the most difficult things to do in our sport,” said Djokovic on court.
“Winning Grand Slams and being number one in the world are probably the pinnacles of the sport. It's been a very long year for all the players and to be able to stand here is a blessing.”