The United States women beat Jamaica for gold in the women's 400-meter relay, smashing the world record for its first Olympic title in this event in 16 years.
The Americans ran the one-lap relay in 40.82 seconds, breaking the old record of 41.37 by over a half-second. That mark was set back in 1985 by the East Germans.
Jamaica set a national record with a time of 41.41 seconds, but still finished .59 seconds behind the American team, which featured Allyson Felix and Carmelita Jeter.
"It's an honor to be part of this team," said Felix, who also won gold in the 200m here in London. "Who would have thought that we would have had a world record tonight? It's amazing. Our names our going down in history."
The Ukraine claimed bronze with another national record time of 42.04 seconds.
Jeter, the silver medalist in the 100 meters here in London, ran the anchor leg of the record-setting race. Just before crossing the finish line, she began pointing at the clock in recognition of the world mark.
"I knew if we got the stick around, then all I had to do was bring it home," said Jeter.
The U.S. has won gold in this race a record 10 times, but this marks its first title since the 1996 Atlanta Games. The Americans have never gone four straight Olympics without winning gold in the women's 400m relay.
Both Jamaica and the U.S. failed to medal in this event four years ago in Beijing. The Americans dropped the baton in qualifying, while Jamaica was disqualified in the final for an illegal handoff.
This year's Jamaican team consisted of Shelly-Ann Fraser-Pryce, Sherone Simpson, Veronica Campbell-Brown and Kerron Stewart, all four of whom have won individual Olympic medals in sprinting events.
The medal was the seventh for Campbell-Brown, placing her second all-time among Jamaican Olympians. Merlene Ottey leads the nation with nine medals.
Heats were also run Friday to set up the finals of the men's 400-meter and the women's 1,600-meter relays. The U.S. posted the top qualifying times for both races.
The American men's team was anchored by Justin Gatlin, winner of the bronze medal in the 100m at the London Games, and posted a national record time of 37.38 seconds. Jeffery Demps, Darvis Patton and Trell Kimmons also ran in the relay for the U.S.
Jamaica, which rested sprinting star Usain Bolt, was second-fastest and only .01 seconds behind the U.S. time. Yohan Blake, runner-up to Bolt at these games in both the 100 and 200, ran the third leg.
Canada qualified in the third position with a time of 38.05 seconds, while Great Britain was disqualified for an illegal handoff.