Shelly-Ann Fraser took Olympic gold in the women's 100m, leading home an unprecedented clean sweep for Jamaica.
Fraser finished in a time of 10.78 seconds, with her compatriots Sherone Simpson and Kerron Stewart sharing the silver medal after a dead heat.
"I'm so excited. I never dreamed this could happen to me," Fraser said.
Britain's Jeanette Kwakye was the only European athlete to make the final, and she performed above expectations with a personal best time of 11.14 for sixth.
The US team asked for the race to be reviewed because of a possible false start by one of their athlete Torri Edwards, who finished last after she felt she had jumped the gun.
US Track & Field felt the race could have been called back but officials rejected the appeal and the result stands.
Kwakye, who took silver in the world indoors earlier this season, said she was pleased to have the opportunity to show what she could do on the biggest stage of all.
"I was living a childhood dream out here," said Kwakye, who was the first British woman to make the 100m final since Heather Oakes in 1984.
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"I'm absolutely shocked and really happy with that time and that performance."
Fraser's gold medal for Jamaica completed a famous double for the country, coming hot on the heels of Usain Bolt's astonishing performance to win the men's 100m in a new world record.
The 21-year-old led from start to finish, and enjoyed a lead of a couple of metres by the time she crossed the finish line.
World silver medallist Lauryn Williams finished fourth in 11.03.
"It was incredibly close," said Williams.
"I tried my best, gave my all and am not frustrated at all.
"To clock 10.78 into a pretty strong headwind is pretty impressive.
"I wasn't thinking about Jamaican speed - I've seem them all year long and they're very consistent."
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