Guillermo Canas advanced to the quarter-finals of the ATP Studena Croatia Open after the No.6 seed rallied past Boris Pashanski of Serbia 6-7 (3-7) 6-3 7-5.
In a match that lasted two hours 45 minutes Canas, who won this tournament in 2004 without losing a set and reached the semi-finals last year, broke at 4-5 in the third set to stay alive.
He is looking to advance to his third semi-final this year, having made it to the final four in Las Vegas and 's-Hertogenbosch.
"I expected a tough match," said Canas, who recovered after dropping the opening set that lasted more than an hour.
"Boris is a very tough player but I am very happy with the way I played. We played for almost three hours with a lot of ups and downs."
Pashanski was disappointed to lose after he had a chance to serve out the match.
"It's tough to close out a match," he said. "Every player feels a little different when trying to serve out a match. The balls are very slow and heavy here, so I knew I would have chances (to break back) even though he was serving for the match."
No.5 seed Ivan Ljubicic was unable to take the court for his match against fellow Croat Roko Karanusic after suffering a sharp pain in his lower back at dinner Wednesday. He underwent three hours of treatment Wednesday night and again on Thursday morning.
"We did everything possible and explored all possible solutions but unfortunately to recover in one day was too much," he said. "I think I need three or more days before making a full recovery. We tried everything from pills, injections and massages."
Another Croat was upset on home turf as No.2 seed Ivo Karlovic was ousted by Maximo Gonzalez 3-6 6-3 6-4. Gonzalez, who overcame 15 aces by the 6-10 Karlovic, the tallest player on the ATP Tour, will take on Karanusic in the quarter-finals.
Ranked 101st in the world, Gonzalez had won just one career match at ATP level prior to this week. Earlier this month, he won the San Benedetto Challenger and in May reached the final of the San Remo Challenger.
Canas will next meet No.4 seed Igor Andreev of Russia, who defeated Spain's Daniel Gimeno-Traver 6-2 7-6 (7-3) in Thursday's final second-round match.
In the quarter-finals in the top half of the draw, top seed Fernando Verdasco of Spain battles German Mischa Zverev and No.3 seed and defending champion Carlos Moya, also from Spain, faces No.7 seed Fabio Fognini of Italy. Moya is seeking his sixth title here.