Pointing the baton at the clock showing the world-record time of 40.82 seconds, Carmelita Jeter anchored the United States on Friday night to its first Olympic gold medal in the women's 4x100-meter relay since 1996.
Tianna Madison, 200-meter champion Allyson Felix and Bianca Knight gave the U.S. a big lead heading into the anchor leg by Jeter, who already owned a silver medal from the 100 and a bronze from the 200 in London.
Their final time cut more than a half-second off the old record of 41.37 run by East Germany in 1985.
Jamaica won the silver medal Friday in a national record of 41.41 seconds, with 100 champion Shelly-Ann Fraser-Pryce, Sherone Simpson, Veronica Campbell-Brown and Kerron Stewart bringing the baton around.
The bronze went to the Ukraine in 42.04.
With Knight approaching for the final handoff, Jeter took nine strides, reached her hand back and took a perfect exchange. Jeter was staring at the clock as she covered the final 10 meters and used the stick in her left hand to make sure everyone else also had their eyes trained on the bright orange numbers on the trackside clock.
Afterward, the quartet of champions paused to watch a replay of their record performance on the scoreboard at 80,000-seat Olympic Stadium. When Jeter was shown crossing the finish line, Knight punched the air.
The perfect trip around the track ended a string of disappointments for the U.S. in the event. At Beijing four years ago, the Americans didn't even reach the final because Torri Edwards and Lauryn Williams bobbled the last exchange in the semifinals.
That marked the first time since 1948 that the U.S. wasn't involved in the women's 4x100 medal race at the Summer Games.