VIENNA — Ernests Gulbis of Latvia upset third-seeded John Isner 6-4, 4-6, 6-4 at the Erste Bank Open on Wednesday to reach his third quarterfinal of the season.
In a match dominated by strong serving, Gulbis hit 23 aces against the American's 16. Each set was decided by just one break though both players had to fight off six break points.
Gulbis, who was on a five-match losing streak coming to this tournament, will next play seventh-seeded Ivo Karlovic or Sergiy Stakhovsky.
In first-round play, fourth-seeded Jo-Wilfried Tsonga beat Tommy Haas 6-3, 6-7 (3), 6-4 in a match between two former champions.