The Swiss player's first trophy of the season gives the 32-year-old world number three a boost ahead of the French Open -- which he won in 2015 -- and where he opens against Slovak Jozef Kovalik on Monday.
"I'm extremely happy to win my second title in Switzerland. It means a lot to me. This is the first time that my daughter is in the stadium when I win the title and that makes it even more special," said Wawrinka yesterday.
"The level was great today, I think it was a great final. Mischa was playing very well and maybe I was hesitating a bit in the beginning," said the Swiss player.
"I'm happy that I came back strongly in the second set and managed to turn the match around."
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Zverev, 29, had been bidding for his maiden tour title in the 33rd-ranked player's first final appearance in seven years.
"Playing on clay is usually not easy for me, but I really felt great here and reaching my first semi-final and final on this surface.