Great Britain's men's team pursuit squad claimed a thrilling Olympic gold in a world record time on the second day of competition at the London 2012 Olympic Velodrome.
Ed Clancy, Geraint Thomas, Peter Kennaugh and Steven Burke clocked three minutes 51.659 seconds to triumph by a supreme margin ahead of arch-rivals Australia.
Australia's Jack Bobridge, Glenn O'Shea, Rohan Dennis and Michael Hepburn finished with silver in 3mins 54.581secs.
The British quartet, who won Track Cycling World Championships gold in Melbourne in April, now have successfully defended the title won by Clancy, Thomas, Bradley Wiggins and Paul Manning in Beijing.
New Zealand's Sam Bewley, Marc Ryan, Jesse Sergent and Aaron Gate claimed bronze in 3:55.952, with Russia's Evgeny Kovalev, Ivan Kovalev, Alexey Markov and Alexander Serov finishing fourth (3:58.282).
Clancy's focus will now turn to the six-discipline omnium, which is set to begin on Saturday.
The victory sparked jubilant scenes from coach Dan Hunt, British Cycling performance director Dave Brailsford and head coach Shane Sutton. It was Britain's second gold medal of the track programme after Sir Chris Hoy, Philip Hindes and Jason Kenny won the men's team sprint on day one.
It was the second time the British quartet had improved the world record they set in Melbourne in April, and they now have the four fastest times in history.
Clancy, Thomas, Burke and Kennaugh soaked up the adulation of the partisan crowd, finding family members around the spectator seating of the velodrome on their laps of honour while waving the Union flag.
Thomas told the BBC: "The amount of work we have had to put in has been unbelievable. In November at Manchester we were up at 7.30 in the morning. They have been on our backs since then. The crowd is just unbelievable. My ears are ringing, it's just too loud."
Ed Clancy, Geraint Thomas, Peter Kennaugh and Steven Burke