Great Britain's Jess Varnish and Victoria Pendleton missed out on a ride-off for Olympic gold after being relegated by officials for a takeover infringement on an eventful opening evening of track action at the London 2012 velodrome.
Varnish and Pendleton had set a world record in the two-woman, two-lap event in qualifying, seeing the mark broken moments later by China.
The Britons set the second fastest time in the first round and were due to advance to the final against China, who set another world record, but officials ruled against them.
Pendleton is set to resume competition in the keirin on Friday, but for Varnish, who has focused on the starting lap in the event, the Games are over.
It meant Germany were promoted to the final against China, with Australia and Holland to contest bronze.
A tearful Pendleton, crowned the queen of the track after her Beijing sprint success, had no qualms with the decision, while 21-year-old Varnish was so devastated she opted out of media duties.
Pendleton said: "It was an illegal change. I came through in the change zone about a metre too early; we're talking about one hundredth of a second of a mistake there.
"Jess moved up a fraction too early and I just saw the door and went for it, because that's my cue to try to squeeze underneath her as quickly as possible.
"It's one of those things that happens. It's quicker than a blink of an eye.
"You have to stick by the rules. The rules are there to make it a fair sport. Unfortunately we fell on the wrong side of that today. It wasn't intentional, obviously."