In the 96 kg category the 28-year-old European champion, Aslanbek Khushtov, outclassed Germany's Mirko Englich to win Russia's third gold medal of the games.
Khushtov said it had been a long struggle "I think it was God's award for all my suffering and hard work."
Adam Wheeler of the United States and Kazakhstan's Asset Mambetov both took the bronze.
In the heavyweight class, the defending Olympic champion, Khasan Baroev, failed to retain his title and had to make do with the silver in the 120kg event losing to Cuba's Mijain Lopez.
Lopez, who clinched Cuba's first gold of the games, said after his victory, "No one can beat Khasan except me. Both of us were in good form."
Mindaugas Mizgaitis of Lithuania and Yury Patrikeev of Armenia both won bronze medals.
