Korkmaz was a part of squad reaching semi-finals of 1989–90 edition of UEFA European Cup. During the 2000 UEFA Cup Final between Galatasaray and Arsenal, he dislocated his shoulder but he declined to quit the game, continued the game until the end following in-field physio treatment where Galatasaray won the cup after extra time. However, the injury caused Korkmaz eventually to miss UEFA Euro 2000 competition.