Anna Meares has defeated her great rival Victoria Pendleton to win Olympic gold in the women's sprint final.
Meares took the final 2-0 and stunned the British crowd who were expecting Pendleton to end her illustrious career on a winning note.
It capped a great night for Australian cycling after Annette Edmondson finished with a flourish to claim bronze in the omnium.
Fireworks fly whenever Meares and Pendleton meet, and the final at the Velodrome was no different.
Meares took the first heat in dramatic circumstances after judges overturned the result in which Pendleton crossed the line only 0.001 seconds ahead.
But the officials noted Pendleton had crossed the red inside sprinting line and as a result she was relegated.
Meares then rode a great tactical race in the second contest and coasted to victory, even having the time to raise her arms in victory as she crossed the line.
"Victoria's such a hard-fought opponent and she's dominated the sport for so long," Meares said.
"It's been such a difficult challenge and to be able to win the Olympic title for me, it's so special.
"I've tried so much and worked so hard for a long period of time and I've asked a lot of people around me to do the same so it feels like this is a just reward."
Meares was tipped to compete for three gold medals in London, but finished third in the team sprint and a disappointing fifth in the keirin.
"I think that a lot of people back home in Australia were disappointed and that felt heavy on me," Meares said.
But she believed she did everything right in the final.
"My coach [Gary West] said to me, 'one race at a time and you nail it and you execute it to perfection,' and I think I did that," Meares said.
Pendleton was quick to congratulate Meares after crossing the line.
"I am glad it got to that stage because I believe she's the best rider in the field," Pendleton said.
"Anna and myself in the final. We have met many a time. I wish her all the best.
"I am glad to say that this is the last time I have to go through this."
But the Briton was upset with her second brush with officialdom this week, having been disqualified from the team sprint for a rule infringement.
That cost her the chance of becoming the first British woman to win three Olympic titles.
"I was really annoyed because I was sure that she touched me and it caused me to move up," Pendleton said.
"I cannot believe twice in one competition that I have been relegated, disqualified, it's unheard of.
"It's a bit of surprise. It did knock my confidence a bit I have to say. I really tried in that last ride.
"This is it. I cannot believe it's all over."
She was, however, relieved.
"I'm so relieved you can't even imagine. It's been the hardest four years of my entire life, coming in as Olympic champion and then realising you've got a home Games to live up to," she said.
"I'm disappointed obviously I didn't win two golds, that would have been perfect, but I'm just overwhelmed with relief right now that I don't have to ever go through that ever again.
"Just being here and just being part of this atmosphere is something I will never forget.
"You wouldn't be able to forget it - it's such a landmark in my life, it's probably the most significant thing that's ever happened to me, so special."
China's Guo Shuang took the bronze after beating Kristina Vogel of Germany.
The much-anticipated gold medal contest came on the final night of competition at the Velodrome.
Pendleton and Meares, the best women sprinters in the world by a distance, have been arch rivals for more than six years.
The Briton relegated Meares to the silver medal in Beijing and won the world title in Melbourne in April.
Meares has had great success in the keirin in recent years but even she lost out to Pendleton in that event earlier in the London program.
It was Meares's second Olympic title after she won gold in the time trial in Athens, while for Pendleton it was a disappointing end to a glittering career that had delivered two Games golds and nine world titles.
Earlier, a bold performance by Edmondson to win the scratch race, the fifth of the six omnium events, put her in the bronze medal position.
The 20-year-old South Australian then sealed a podium place by posting the second fastest time (35.140) in the 500m time trial.
She had earlier finished third in the elimination race, third in the flying lap, fourth in the individual pursuit and fourth in the points race.
"To be honest I came here wanting more. I wanted gold or silver but stuffed up the points race a little bit," she said.
"I couldn't face going home with nothing, so to get bronze is brilliant. I am so happy to be able to take something home, especially after we didn't win the bronze in the team pursuit (Australia came fourth).
"I did this for my team-mates back home. It is my first medal at the Olympics and I can't believe it, it's something special."
Edmondson admitted she was nervous overnight after the first four events on Day 10.
"I thought they were two tough events today but I wanted to give it the race of my life. I knuckled down and managed to do things right in the scratch race."
Britain's Laura Trott claimed the gold, her second of the Olympics, pipping Sarah Hammer of the United States by one point after winning a thrilling time-trial finale.