Born in Metkovic, Croatia, Petković began his youth career with Dinamo Zagreb, where he remained until 4 September 2009, when he transferred across town, to the youth academy of city-rivals NK Zagreb.
Born in Metkovic, Croatia, Petković began his youth career with ONK Metković, and he went to Dinamo Zagreb. He remained there until 4 September 2009, when he transferred across town, to the youth academy of city-rivals NK Zagreb.