Kammala jumla mai zuwa: A lokacin barkewar yakin basasa na Spain, Petrović ya zaɓi ya shiga yaƙin a gefen Jamhuriyar Spain kuma ya tafi Spain tare da abokinsa Sreten Dudić a ƙarƙashin sunan Fernández García. Bayan isowarsu, an tura matukan jirgin biyu a kan horo na kwanaki 26 a Albacete kafin a tura su zuwa gaba. Bayan ya shiga cikin fadace-fadace da dama, ciki har da
Siege na Madrid, an kashe Petrović a ranar 12 ga Yuli, 1937, a ranar da ya sami kisansa na biyar da aka tabbatar. Ba da daɗewa ba bayan mutuwarsa, ɗan'uwansa Dobre ya isa Spain kuma ya ɗauki matsayinsa a cikin rundunar.