At his first major international competition, Zorko finished sixth in the men"s 3000 metres race at the 1989 IAAF World Indoor Championships.
Zorko competed in the 1500 metres in five Olympic Games, from 1988 to 2004, making it through to the semi-finals in 1992 and 1996. In 1992 he was awarded the Franjo Bučar State Award for Sport. Competitive career
Before the breakup of Yugoslavia, Zorko was a formidable long-distance runner who was very competitive in the 3000 metres and 5000 metres disciplines.
After the breakup of Yugoslavia, Zorko began specializing in middle-distance disciplines, and eventually found his talent in the 1500 metres.
Next year, Zorko finished second in the 1500 at the 1994 European Athletics Indoor Championships, and third at the 1994 European Championships in Athletics. At the 1997 IAAF World Indoor Championships and at the 2002 European Indoor Athletics Championships, he finished in fourth place in the respective 1500 metre races.
Pacing career
By the late 1990s, Zorko was increasingly suffering from injuries, which prompted him to turn to professional pacemaking. As a pacemaker, he assisted in setting several world records, both indoors and outdoors, most notably for Haile Gebrselassie.
Retirement
As of 2012.
Outdoors
Indoors.