The Finals, contested by the world's top eight singles players and eight doubles teams, was moved out of China's Shenzhen after last year's event was cancelled due to the COVID-19 pandemic.
The Australian Open champion never faced a break point and used her hard and accurate serve to dispatch Gauff.
IMAGES from Day 5 of the Wimbledon Championships at All England Lawn Tennis and Croquet Club on Friday.
Zverev's serve played a big role in the victory, his third of the year, as the World No 3 won all but two of his first-serve points in the final, which lasted 74 minutes.