UMAG, Croatia (AP) -- Andreas Seppi of Italy advanced to the quarterfinals of the Croatia Open when Andreas Haider-Mauer retired with an injury while trailing 6-1, 4-0 on Thursday.
Haider-Mauer started well, winning the opening game, but then lost 10 straight games. He sought medical treatment for a lower back injury after the first set and retired in the second.
Horacio Zeballos from Argentina also advanced after rallying to defeat eighth-seeded Carlos Berlocq 3-6, 6-3, 6-2.
Seppi is making his fourth appearance in the quarterfinals at Umag in as many years. He improved to 9-3, with his best result the semifinals in 2009 and 2010 - when he lost both times to Spain's Juan Carlos Ferrero.
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