VIENNA, Oct. 11 (UPI) -- Unseeded Bohdan Ulihrach of the Czech Republic marched into the quarterfinals by rallying for a three-set victory Thursday over Tommy Robredo of Spain at CA Tennis Trophy.
Ulihrach, who knocked off top seed Yevgeny Kafelnikov of Russia in the second round, recovered for a 1-6, 6-3, 6-4 victory over Robredo. He had been winless in two previous encounters with the Spaniard.
Ulihrach's reward is a quarterfinal matchup with sixth-seeded Tommy Haas of Germany, who dispatched Czech Jiri Novak, 7-6 (7-3), 6-3.
The other quarterfinal in the top half of the bracket will pit Thomas Enqvist against Swedish compatriot Andreas Vinciguerra. Enqvist eliminated Alberto Martin of Spain, 6-2, 7-5, and Vinciguerra got past Adrian Voinea of Romania, 6-4, 7-5.
Federer's next foe is Stefan Koubek of Austria, a wild card entry who held off American Michael Chang, 6-3, 3-6, 7-5.
Also advancing to the round of eight was unheralded Michel Kratochvil of Switzerland, who beat Jurgen Melzer of Austria, 7-6 (7-4), 7-6 (7-5).
Kratochvil will face Guillermo Canas of Argentina, who upset second-seeded Brit Tim Henman in Wednesday's quarterfinal. Canas also beat Henman at the French Open.