Zverev broke the Swiss top seed's serve twice for a one-set lead in 39 minutes on Sunday in the St Petersburg ATP final on the hardcourt of Sibur Arena.

In the second set, world number three Wawrinka broke Zverev's serve twice to level at one-set all after one hour 22 minutes on court.

The 31-year-old Wawrinka broke early in the deciding set but Zverev broke back twice to close out his win in two hours 23 minutes, to claim his debut ATP title 6-2, 3-6, 7-5.

"I'm full of emotions! I just couldn't have chosen a better place to win my maiden title," said Zverev, who has Russian origins.

Hamburg-born Zverev is the son of former Russian Davis Cup player Alexander Zverev Senior and the younger brother of US Open semi-finalist Mischa Zverev. He lives in Monaco.

"It was really hard when I was trailing 3-0 in the deciding set but I forced myself to keep on fighting. And now I'm really happy with my win," Zverev said.

In July 2016 he had become the youngest player to enter the ATP top 25 since Novak Djokovic in 2006.

His opponent Wawrinka had won eleven of his previous ATP finals. He congratulated the young German: "You're the future of the tennis but you're already at the top," Wawrinka commented. "Today you've played a great match and won deservedly. My congratulations for what you're doing so far."

jm/es (AFP, Reuters)