UMAG, Croatia -- Second-seeded Andreas Seppi of Italy advanced to the quarterfinals of the Croatia Open on Thursday, after leading Andreas Haider-Mauer 6-1, 4-0 before the Austrian retired through injury.
Haider-Mauer started well, winning the opening game, but then lost 10 games in a row. He sought medical treatment for a lower back injury after the first set and then retired in the second.
"I have no idea when his problems started," Seppi said. "I tried to focus on my game and did not notice that anything was wrong with him."
It will be Seppi's fourth appearance in the quarterfinals at Umag in as many years. He improved his record to 9-3, with his best results being the semifinals in 2009 and 2010 -- when he lost both times to Spain's Juan Carlos Ferrero.
Horacio Zeballos from Argentina also advanced after rallying to defeat eighth-seeded countryman Carlos Berlocq 3-6, 6-3, 6-2.
Berlocq, who had won all but one of the last nine matches, including his first career title two weeks ago in Bastad, started off well but made too many unforced errors in the second and third set.
After winning the second set, Zeballos was up in 3-0 in the third before Berlocq produced a rally of his own to reach break point for 3-3. However, Zeballos saved it, and then cruised to victory.
Later, Aljaz Bedene from Slovenia defeated fourth-seeded Alexandr Dolgopolov 6-3, 6-1.
Dolgopolov, who won this event in 2011, soon struggled to keep up. Bedene, currently ranked 100, won nine out of 10 games as he accelerated away from 2-2 to 6-3 and 5-0.
Bedene lost only two points in the second set before Dolgopolov finally managed to win a game. But in the next game, the Ukrainian was broken again at love. Umag will be the second quarterfinal of the year for Bedene, who was a semifinalist in Chennai in the opening week of the season.
Meanwhile, Spaniard Tommy Robredo won in straight sets to reach the quarterfinals, defeating Viktor Toricki of Serbia 6-0, 6-4.