In a match between two wild-card entries, Ivanisevic eventually triumphed on his fifth match point, winning 6-3, 6-3 in 79 minutes.
Ivanisevic is one of three players in Antwerp who are in the running for the final place in the eight-man ATP finals. The others are Cedric Pioline, of France, who beat Germany's Marc Goellner 6-3, 7-6 to earn a quarter-final match against Ivanisevic, and Boris Becker, who also reached the last eight after beating American Chuck Adams 7-6, 6-4. The three- times Wimbledon champion needed a third set point to take the tie-break 9-7.
The American, Michael Chang, clinched the seventh place yesterday. Chang failed to obtain a wild card for Antwerp but results this week involving other players mean he has now qualified.
The Americans Pete Sampras and Jim Courier, Germany's Michael Stich, Sergi Bruguera of Spain, Sweden's Stefan Edberg and Andrei Medvedev of the Ukraine are the others already through.