DALLAS -- John Isner won a pair of tiebreakers in a match without any service breaks, advancing to the second round of his hometown Dallas Open with a straight-sets victory over Chun-Hsin Tseng on Tuesday night.
The fifth-seeded American served 22 aces in a 7-6 (5), 7-6 (1) victory that left Isner with a 498-319 career record in tiebreakers. Tseng, 21, was playing just his 10th and 11th tiebreakers, falling to 3-8.
Marcos Giron, the No. 7 seed who reached the semifinals of the inaugural event last year along with Isner, advanced with a 6-4, 6-7 (1), 6-1 victory over Alex Rybakov earlier Tuesday.
Eighth-seeded Adrian Mannarino of France won the final five points of a first-set tiebreaker and the last four games of the second to beat American Steve Johnson 7-6 (6), 6-2.
J.J. Wolf, the No. 6 seed, had little trouble in a 6-3, 6-3 victory over fellow American Brandon Holt.
The 5-foot-9 Tseng stayed on serve with the 6-10 Isner, the tour's career leader in aces, before Tseng finally faltered in the second-set tiebreaker.
The match was all but over when Isner won consecutive points on Tseng's serve for a 4-1 lead. Isner, 37, won the final six points of the tiebreaker.
"I was a little bit worn out after that first set emotionally," Isner said. "But I was able to stay even in the second set and I played a really, really good tiebreaker. And I'm very happy I'm not still on this court."
Giron responded quickly after failing to close out the second set, winning the first five games of the deciding set.
Rybakov broke his fellow American when Giron was serving for the match in the second set. Then Rybakov won the first six points of the second-set tiebreaker.
"I'm really happy with how I was able to reset in the third and just get back to the game plan from the beginning and elevate," Giron said. "He played well and served well and kind of hung in there."
American Mackenzie McDonald was a 6-3, 6-0 winner over Fernando Verdasco of Spain and will face second-seeded Frances Tiafoe of the U.S. in the second round.
Wolf will face Radu Albot, who rallied for a 2-6, 6-4, 6-2 victory over American wild-card entry Liam Krall.