German teenager Alexander Zverev stunned US Open champion Stanislas Wawrinka to claim his first ATP title at the St Petersburg Open.
The 19-year-old came from a break down in the deciding set to win 6-2 3-6 7-5.
Zverev is the first man to beat Wawrinka in a tour final since 2013 and also ended his 10-match winning streak.
Briton Dominic Inglot and Finland's Henri Kontinen beat Russia's Konstantin Kravchuk and Andrey Kuznetsov 6-3 6-0 to win the doubles title.
"I'm full of emotions. I just couldn't have chosen a better place to win my maiden title," said Zverev.
"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."