Bulgaria's Semen Novikov denied Iran a second Greco-Roman gold by winning the 87kg event with a 7-0 romp against Mohmadi, who took silver.
Novikov scored first on passivity and got a lift for two in the first period. He added two more early in the second and one for a step-out to surge far ahead.
Earlier in the day, Saeid Esmaeili had won a gold medal for Iran in the 67kg.