The fifth-ranked German overwhelmed Russian opponent Karan Khachanov 6-3, 6-1 at the Tokyo Games on Sunday for the biggest title of his career.
The 6-foot-6 (1.98-meter) Zverev controlled the match with his big serve and a confident two-handed backhand, never really giving the 25th-ranked Khachanov a chance.
Zverev's previous best performance was reaching the final of last year's U.S. Open, where he wasted a two-set lead in a five-set loss to Dominic Thiem.
IOC president Thomas Bach watched his fellow German win the title as a group of about 10 anti-Olympic protesters across the street from the Ariake Tennis Park made themselves heard inside Center Court. Play was not interrupted. (AP)