TURIN, Italy (AP) — Strong serving and consistent baseline play propelled U.S. Open champion Daniil Medvedev to a 6-7 (5), 6-3, 6-4 win over first-time qualifier Hubert Hurkacz in the opening match of the ATP Finals on Sunday.
In the day's second match, 2018 champion Alexander Zverev won when local favorite Matteo Berrettini of Italy retired early in the second set with an apparent abdominal injury.
Zverev won the first set 7-6 (7) and was leading 1-0 in the second when Berrettini dropped his racket to the ground, covered his face and bent over in apparent pain.
"The atmosphere was one of the best I felt ever in my life and that's why it feels so bad right now," Berrettini said. "The worst thing that could have happened happened."
The result moved Zverev ahead of Medvedev atop the Red Group in the round-robin format.