France's Jo-Wilfried Tsonga defeated compatriot Gael Monfils 6-3, 7-6 (10-8), in a first-round match at the Japan Open on Monday.
Tsonga, ranked eighth in the world, used a strong serve and powerful ground strokes to win a baseline battle with Monfils at Ariake Colosseum in 1 hour, 31 minutes.
In other first-round matches, sixth seed Nicolas Almagro of Spain eliminated qualifier Benjamin Becker of Germany 7-6 (7-4), 7-6 (7-3), while Alexandr Dolgopolov of Ukraine downed Daniel Brands of Germany 6-3, 6-1.