Allyson Felix won her third gold medal of the London Olympics, giving the United States a 20-meter lead after the second leg of the 4x400-meter relay and then watching teammate Sanya Richards-Ross bring home the victory Saturday night.
The U.S. runners finished in 3 minutes, 16.87 seconds for the country's fifth straight Olympic title in the event. Russia finished second in 3:20.23 and Jamaica was third in 3:20.95.
DeeDee Trotter ran the opening leg for the United States and built a lead before handing to Felix, who more than doubled the advantage by the time she passed to Francena McCorory.
Richards-Ross had a stress-free anchor leg to add this gold medal to her 400-meter gold. Felix earlier won the 200 and 4x100 relay.