Olympics judo: Russia's Mansur Isaev takes -73kg gold
Mansur Isaev of Russia won gold in the men's -73kg final by beating world champion Riki Nakaya of Japan.
Isaev, 25, was an outside favourite for the title after only finishing seventh at last year's World Championships.
The bronze medals were won by Nyam-Ochir Sainjargal of Mongolia and Ugo Legrand of France.
Great Britain's Daniel Williams lost his opening fight by ippon throw from the 2008 Olympic bronze medallist, Rasul Boqiev of Tajikistan.
Disappointed Williams, 23, left without speaking to reporters but his coach, Luke Preston, said: "Danny did everything right really and he just got caught when the guy got his chance, but that is judo.
"He was fighting an Olympic bronze medallist and just got caught that one second and it was all over."
Fourth seed Isaev overcame world number one Wang Ki-Chun of South Korea before seeing off Nakaya to secure gold.