Chris Hoy won the men's sprint to take Great Britain's gold medal tally to six at the Track Cycling World Championships in Manchester.
Hoy's victory makes him the first rider to win world titles in track cycling's four speed events - the kilometre, team sprint, keirin and sprint.
The 32-year-old Scot twice overcame the young Frenchman Kevin Sireau to win both legs of the final.
Mickael Bourgain of France took bronze ahead of Italy's Roberto Chiappa.
Hoy, competing in the sprint for the first time, was taken to a third deciding race in the quarter-finals by the Netherlands' Theo Bos.
But the former kilo world champion got his tactics spot on in both the semi-final and final.
Hoy's sprint victory is Great Britain's first since Reg Harris won the event in 1954.
"This is right up there with anything I've ever done before, including Athens [in 2004]," Hoy told BBC Sport.
"To win the world title in front of the home crowd is hard to put into words."
He went on to explain how he has managed to adapt to the change in disciplines: "It's not been easy. Kilo riders have a reputation for being a bit stupid.
"And I was no exception to that rule; having the power but not being sharp mentally.
"Thankfully I've managed to learn relatively fast, and with Beijing coming up, it's hopefully a realistic medal chance there too."
Earlier, Rebecca Romero claimed her second gold medal of the championships as the British women's pursuit team set a new world best in beating Ukraine.
Together with Wendy Houvenaghel and Jo Rowsell, Romero set a time of 3mins 22.415secs in the event's debut.
Germany beat Belarus in the third-place race to take bronze.
Although Ukraine started quicker and led at the 1,000m mark, the British team had overhauled them after two kilometres.
And then, as the Ukraine team began to fragment, the Britons sped away to victory.
606: CommentRomero told BBC Sport: "What a buzz! I can't take this for the second day in a row.
"We had minimal preparation and hadn't even had any race practice but we were awesome."
Rowsell, just 19 years old and riding in her first world championships, added: "I'm so happy to step up to their level, it's amazing. It was very nerve-wracking but I just focused on the job of delivering the team at speed.
"Team GB has been so successful at track cycling and I've had a really great time."
In the men's points race, won by Vasili Kiryienka of Belarus who finished just one point ahead of France's Christophe Riblon, Great Britain's Mark Cavendish finished equal 15th.
Victoria Pendleton, favourite in the women's sprint final, has the chance to equal Britain's tally of seven golds from last year's championships on Saturday.
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