Fourth-seeded Frances Tiafoe opened with a 6-3, 6-4 victory over wild card Yasutaka Uchiyama in first-round action of the Japan Open Tennis Championships on Monday.
Eight aces helped Tiafoe win in one hour, 14 minutes.
Fellow American Brandon Nakashima, who won his first ATP Tour title last month in San Diego, earned a 6-3, 6-2 win over Japanese wild card Shintaro Mochizuki while a pair of Spaniards also advanced via straight-set victories. Pedro Martinez defeated Aussie Alexei Popyrin 7-5, 6-4 and Bernabe Zapata Miralles topped Taro Daniels of Japan 7-5, 7-5.
Poland's Hubert Hurkacz defeated Argentine Francisco Cerundolo 6-2, 7-6 (2) in first-round action in Astana, Kazakhstan.
The seventh-seeded Hurkacz recorded 11 aces and won 80 percent of his first serves to advance.
Frenchman Adrian Mannarino defeated wild card Stan Wawrinka 1-6, 6-2, 6-3, Botic van de Zandschulp of the Netherlands cruised past wild card Beibit Zhukayev of Kazakhstan 6-1, 6-1, and Chinese qualifier Zhizhen Zhang rallied past Russian Aslan Karatsev 4-6, 6-4, 6-1.
--Field Level Media