British cyclist Chris Hoy clinched a hat-trick of gold medals as he beat team-mate Jason Kenny in the sprint.
The 32-year-old becomes the first Briton in 100 years to win three golds at the same Olympics, after his earlier success in the team sprint and keirin.
The Scot was pushed to the limit in the first race by his 20-year-old opponent, edging the opening duel in the best-of-three by half a wheel's length.
Hoy dominated the second race, giving a victory salute as he crossed the line.
"I cannot tell you how it feels - it is amazing," Hoy told BBC Sport.
OLYMPICS BLOG
"When you cross the line, all the pressure that has built up, the expectation and the self doubt evaporates just like that.
"When you want something that much and the hours you put in, it is an amazing feeling when you achieve it."
Hoy becomes only the second Briton to win three golds at the same Games after swimmer Henry Taylor did likewise in London in 1908.
And he added: "I was vaguely aware of the history, people tell you about it. But I tried to make it the furthest thought from my mind.
"And that's why the emotions come out at the end. You bottle it for so long that it just erupts at the end."
Hoy has now won gold in four separate Olympic events - he won the now-defunct 1km time trial at Athens in 2004.
British cycling's performance director Dave Brailsford hailed Hoy as a "true Olympic athlete".
"He's resilient and he does genuinely embody those Olympic values of fair play and working hard, and he is the real deal," said Brailsford.
"He's a true gentleman and to me he embodies what a true Olympic athlete is meant to be."
Kenny's silver adds to his impressive showing in his first Olympics, where he also picked up gold in the team sprint - alongside Hoy and Jamie Staff.
Hoy was quick to pay tribute to Kenny, and tipped him to become the dominant force in cycling in the next few years.
"Kenny has come through the ranks and he is the man who will win at London 2012," said Hoy.
OLYMPICS BLOG"Beating him was really tough - it was probably the hardest race of my life."
The bronze medal went to Mickael Bourgain of France after he dominated Germany's Maximilian Levy in a third-leg decider.
Hoy's gold was the last to be decided in the velodrome and left the British team with an incredible haul of seven golds from a possible 10 in track cycling in Beijing.
It was also Team GB's 15th gold medal of the Games, keeping them third in the medal table.
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