The 200-meter champion ran a blistering second leg and 100-meter silver medalist Camelita Jeter finished off the world record performance, pointing to the time clock with her mouth wide open as soon as she got past the finish line, seeing that the 27-year-old mark of the former East Germany was gone.
The U.S. team finished in 40.82 seconds, shaving a massive 0.55 seconds off the old mark.
"Who would have thought that we would have had a world record tonight?" Felix said. "It's amazing. Our names are going down in history."
Jeter was just as elated. "I was already pointing at the clock, saying 'there it is!' There was a cloud hanging over us with people saying 'they cannot do this, they are going to drop the stick,' but we did it."
It was the second world record in as many days on the super-fast track at the Olympic Stadium after David Rudisha of Kenya set a fresh mark 800 on Thursday night.
Almost as amazing as the U.S. women's relay record was the stunning loss by the U.S. men's 4x400 relay after it had won every Olympic gold medal in the event since boycotting the 1980 Moscow Games.
In a thrilling finish, Ramon Miller chased down and swept past Angelo Taylor in the final straight to deprive the United States of a gold it long thought it had a lock on.
It overshadowed the last race at the London Games of Oscar Pistorius, who got the South African baton in last place and crossed the line in eighth in an anticlimactic performance after he had become the first amputee runner in track and field to compete at the Olympics.
No one came close to a world record in the 5,000, but Meseret Defar reclaimed the title she first won eight years ago, as her Ethiopian compatriot Tirunesh Dibaba missed a chance to become the first woman to repeat as double Olympic long-distance champion.
Defar swept past the front-running Dibaba in the final straight and had enough power to hold off Vivian Cheruiyot of Kenya. Dibaba, running with blue tape on the back and inside of her right thigh, faded toward the end and was unable to produce the kick that earned her gold in the 10,000 last week.
Once she crossed the line, Defar produced a religious image of a virgin and child to show to the cameras before breaking down, sobbing into the picture.
After she won at the 2004 Athens Games, Defar has often had to spend time running in the shadow of Dibaba. Now the two have combined to dominate their fierce rivals from Kenya over the long distance events in London.
"I feel like I've been born again," Defar said. "After eight years, to get gold again is big."
Ethiopia had already won the women's marathon in the center of the city last Sunday, and the favored Cheruiyot failed to even get close to her world championship double from last year.
Dibaba was one race away from achieving the long-distance equivalent of what Usain Bolt did over the sprints on Thursday.
Bolt's double in the 100 and 200 turned him into a self-proclaimed "living legend," and he rested on Friday while his 4x100 relay teammates toiled.
The Jamaican relay team still easily qualified for Saturday's final in 37.39 seconds, the fourth-fastest time in history at that stage. Then the U.S. team trumped them with 37.38 seconds for a U.S. record.
On Saturday, Bolt will have chance to show if he can make enough of a difference on the fast track to produce another world record in the finale of the weeklong U.S-Jamaican battle for sprint supremacy.
Alsi Cakir Alptekin led Gamze Bulut in a 1-2 finish for Turkey in the 1,500 final. Two-time world champion Maryam Jamal of Bahrain took bronze.
U.S. runner Morgan Uceny had another tumble at a major meet, crashing to the track at the start of the last lap and failing to finish the final. She was the leading 1,500 runner leading into the world championships last year but fell in the final at Daegu.
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