Cannot play media. Sorry, this media is not available in your territory.
Video - Tishchenko breaks boxing record
Russia's Alexey Tishchenko became the first boxer in 30 years to win Olympic gold in two different weight divisions with victory over France's Daouda Sow.
The 24-year-old was hot favourite to win his lightweight bout but his taller opponent kept the contest close.
The Athens featherweight champion won the first two rounds before Sow fought back to take the third.
He took a 10-8 lead into the last round which was cut by Dow before the Russian scored again to secure the gold medal.
"The level of boxing has become more equal, all opponents are difficult," said Tishchenko.
"In today's bout I was faster than him."
Sow added: "I accept the defeat. I believed in victory until the very end.
"We will not start a review of the judging system now.
"I have to move on, life goes on. I'm not totally satisfied with the result but somehow he's been better than me.
"Today I wanted gold but I got silver. Sometimes you have to know how to lose."