New Delhi, Nov. 10 -- Germany's Alexander Zverev made a strong start to his ATP Finals campaign, defeating America's Ben Shelton 6-3, 7-6(6) in Turin on Sunday.

Zverev made his return to competition at the Nitto ATP Finals in Turin, overcoming a swollen ankle injury that had plagued him in his semi-final loss to Jannik Sinner at the Rolex Paris Masters, as per the ATP website.

"He's an unbelievably aggressive player. Probably one of the most aggressive in the world. In the tie-break, he started off amazing. Yes, I missed maybe one or two first serves, and the passing shot he hit (at 5/4) was ridiculous. I felt like I had to control the things that I could control, and I was doing them well," Zverev said.

"At the end of the day, when th...