Vienna - Gilles Muller of Luxembourg defeated two-time former champion Jurgen Melzer of Austria 6-3, 3-6, 7-6 (7/4) to reach the Erste Bank Open quarter-finals on Wednesday.
Muller broke the fourth-seeded Melzer twice in the opening set but had no break points on the Austrian's serve afterward. He converted his first match point with a return winner in the third-set tie-breaker.
Melzer, the 2009 and 2010 winner who had a bye in the first round, had not lost his opening match in his home event since 2004.
In first-round play, Donald Young of the United States won his fifth match of the season by defeating Fabio Fognini 7-6 (10/8), 6-3.
Young was two breaks up before the fifth-seeded Italian won four straight games to take the opening set into a tie-breaker. Young, who dropped from 38th to 187th this year, saved six break points in the second.
Also, Austrian wildcard Dominic Thiem, ranked 394th, beat Lukas Lacko of Slovakia 7-6 (7/3), 6-3.
Results from the second day of the Austrian Open on Wednesday (x denotes seeding):
Donald Young (USA) bt Fabio Fognini (ITA x5) 7-6 (10/8), 6-3
Dieter Thiem (AUT) bt Lukas Lacko (SVK) 7-6 (7/3), 6-3
Gilles Muller (LUX) bt Jurgen Melzer (AUT x4) 6-3, 3-6, 7-6 (7/4)