Umag, Croatia - Former champion Fernando Verdasco of Spain defeated Ernests Gulbis of Latvia 6-2, 3-6, 6-1 to reach the Croatia Open quarter-finals on Thursday.
Verdasco, the top-seed and 2008 champion, converted five of 18 break points in the second-round victory.
Gulbis served eight aces but could not counter Verdasco, who picked up his game in the third set.
Verdasco will next face either Andrey Kuznetsov of Russia or Mate Pavic of Croatia. Pavic ousted second-seeded countryman Marin Cilic.
Fifth-seeded Carlos Berlocq beat fellow Argentine Marco Trungelliti 7-6 (7/4), 4-6, 6-1. Berlocq converted eight of 16 break points, but his five double faults gave Trungelliti hope.
Results from the fourth day of the ATP tournament on Thursday (x denotes seeding):
Fernando Verdasco (ESP x1) bt Ernests Gulbis (LAT) 6-2, 3-6, 6-1
Andrey Kuznetsov (RUS) bt Mate Pavic (CRO) 7-6 (7/0), 6-1
Carlos Berlocq (ARG x5) bt Marco Trungelliti (ARG) 7-6 (7/4), 4-6, 6-1
Alexander Dolgopolov (UKR x3) bt Fabio Fognini (ITA) 6-2, 6-4