Russia's Arsen Galstyan celebrates after defeating Japan's Hiroaki Hiraoka in their men's -60kg final judo match, at the London 2012 Olympic Games July 28, 2012. [Photo/Agencies]

LONDON - Arsen Galstyan became Russia's first Olympic judo winner since the collapse of the former Soviet Union and dedicated his gold medal to those affected by recent floods in his homeland.

"I feel absolutely wonderful," said Galstyan, 23, who stunned firm favourite and world number one Rishod Sobirov of Uzbekistan on his way to victory.

"My medal will mean a lot, especially (to) people who are suffering from the flood."

Flash floods earlier this month killed 171 people and damaged more than 4,000 homes in the region of southern Russia from where he hails.

Galstyan's route to gold could hardly have been harder. Having only just overcome South Korean Choi Gwang-Hyeon, his close encounter with Sobirov, who had been aiming to add an Olympic gold to his two successive world titles, was only settled with a waza-ari throw in the extra time golden score period.

In the final, it was a different matter, beating Japan's Hiroaki Hiraoka, silver medallist at last year's world championships, with an ippon, an automatic winning score, just 40 seconds into their clash.

He joined jubilant Russian team mates in celebrations in front of a standing ovation from a crowd which included a large number of disappointed Japanese fans.

"I always imagined this situation. I always had hope," Galstyan added. "My medal will show that Russian judo athletes and Russian sport should be number one."

Hiraoka, who suffered disappointment when losing in the first round in Beijing four years ago, was unhappy to only take silver in London.

"I worked really hard for the last four years and still I'm not satisfied with the colour of my medal but I did the best that I can," he said.

A clearly downhearted Sobirov, 25, a bronze medallist in Beijing four years ago, secured a second Olympic bronze by beating France's Sofiane Milous.

Brazil's Felipe Kitadai took the other bronze, beating Italy's Elio Verde.