Azerbaijan's Toghrul Asgarov shocked Russia's three-time world champion Besik Kudukhov to win men's freestyle 60kg gold in two periods at ExCeL.
Asgarov controlled the bout from the start and narrowly earned a 1-0 first-round win, before dominating the second in a comfortable 5-0 success.
"Asgarov didn't let the Russian get anywhere near him. He just kept attacking and attacking. Sometimes attack is the best form of defence."
It was sweet revenge for Asgarov after he was beaten by Kudukhov in last year's world final.
USA's Coleman Scott and Yogeshwar Dutt of India each claimed bronze.
Scott produced a stunning turnaround to snatch bronze away from Japan's Kenichi Yumoto in a 2-1 win.
Yumoto, bronze medallist at Beijing 2008, edged the opening two-minute period 1-0 before succumbing 3-0 and 3-1 to the American in the final two rounds.
A decider was also necessary in the other bronze-medal match between Dutt and his North Korean opponent Ri Jong-Myong.
Delhi policeman Dutt won his nation's first Olympic wrestling medal with a 0-1 1-0 6-0 win.