Yazdani erased a 6-0 deficit to defeat Geduev in the 74 kg freestyle, winning on tie-breaking criteria.
Yazdani has now won gold medals at the Junior Wrestling World Championships, Wrestling World Cup (2015 and 2016) and Olympics, and last year he took silver at the Wrestling World Championships in Las Vegas.
Earlier on the day, Hassan Rahimi claimed a bronze medal in the 57kg, defeating Cuba's Yowlys Bonne 5-0.
Iranian athletes have won three gold medals (weightlifting and freestyle wrestling) and four bronze medals (Greco-Roman, freestyle wrestling and taekwondo) so far.
