Kaori Matsumoto of Japan won the women's under-57kg category at the Olympic judo event on Monday after Romania's Corina Caprioriu was disqualified in the final.
Caprioriu made an illegal attack from behind, earning an automatic disqualification during a sudden death golden score period in an otherwise tight final.
By winning gold Matsumoto ended the Japanese women's judo medal drought at the Games.
American Marti Malloy beat Beijing champion Giulia Quintavalle of Italy with a brilliant foot sweep (kouchi-gari) to claim bronze.
The other bronze medal went to Automne Pavia under the watchful gaze of French president Francois Hollande.