LONDON -- Eyeing the trackside clock as she approached the finish line, Carmelita Jeter pointed the black baton in her left hand at those bright orange numbers.
She wanted to make sure everyone saw what she saw: The United States was breaking the world record in the women's 4x100-meter relay.
Allyson Felix, Tianna Madison and Bianca Knight built a big lead, and Jeter brought it home Friday, anchoring the United States to its first Olympic gold medal in the sprint relay since 1996 with a time of 40.82, more than a half-second better than the world record.
"As I'm running, I'm looking at the clock and seeing this time that's like 37, 38, 39. In my heart, I said, 'We just did it!' I definitely knew we ran well," Jeter said.
"When I crossed the finish line, I had so many emotions because we haven't been able to get the gold medal back to the U.S."
Felix collected her second gold of the Games, along with her gold in the 200, while Jeter completed a set, adding to her silver in the 100 and bronze in the 200.
"I just knew if we had clean baton passes that we would definitely challenge the world record. Smash it like we did? We had no idea," Madison said.
"But I knew it was in us."
The American quartet erased the old mark of 41.37 run by East Germany in October 1985.
Jamaica won the silver medal in a national record of 41.41 seconds, with a team of 100 champion Shelly-Ann Fraser-Pryce, 100 bronze medalist Veronica Campbell-Brown, Sherone Simpson and Kerron Stewart. The bronze went to Ukraine in 42.04.
Madison ran the opening leg, and Felix the second. Then, with Knight approaching for the final handoff, Jeter took nine strides, reached her hand back and took a perfect exchange.
The U.S. performance was part of a speedy night on the track. The United States and Jamaica turned in two of the five fastest men's 4x100 relays in history to set up a showdown in today's final.
In the 4x400, Ramon Miller of the Bahamas overtook Angelo Taylor of the United States to give his country its first men's Olympic gold medal in any sport.
Miller powered Bahamas to a time of 2:56.72, 0.33 seconds better than the Americans, who had won that event at every Olympics since 1984. Trinidad and Tobago took third. The United States was missing three injured runners, including Manteo Mitchell.
The South African team and double-amputee Oscar Pistorius finished last.
In the 4x100 semifinals, dash bronze medalist Justin Gatlin ran the anchor leg as the Americans broke a 20-year-old national record by finishing in 37.38 seconds.
Jamaica ran 37.39 in the other semifinal -- and that was without Bolt, who got a chance to rest.
"We're going to figure out a way to go out there and compete with them," Gatlin vowed. We're not scared of them."
The current world record of 37.04 was set by Jamaica last year.olympics