The U.S. runners finished in 3 minutes, 16.87 seconds for the country’s fifth consecutive Olympic title in the event. Russia finished second in 3:20.23.
DeeDee Trotter ran the opening leg for the U.S. 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.
Other gold winners were Mo Farah, of Britain, in the men’s 5,000 meters; Anna Chicherova, of Russia, in the women’s high jump; Keshorn Walcott, of Trinidad and Tobago, in the men’s javelin; and Mariya Savinova, of Russia in the women’s 800, with Caster Semenya, of South Africa, getting the silver three years after being forced to take gender tests.
DIVING: David Boudia ended a gold-medal drought for the United States with a dramatic last dive that scored the most points of the 10-meter platform competition.
Boudia scored 90.75 on his last dive and finished with 568.65 points. His victory by 1.08 points over Qiu Bo, of China, gave the U.S. its first gold in diving since 2000.Tom Daley, of Britain, settled for the bronze.
SOCCER: Oribe Peralta scored 29 seconds into the final and added another goal in the second half to help Mexico upset Brazil 2-1.
It was fastest Olympic goal since FIFA began keeping records in 1976.
Brazil was trying to win its first Olympic gold.
VOLLEYBALL: Brazil denied the United States its first Olympic gold medal in women’s play in a 11-25, 25-17, 25-20, 25-17 upset.
BOXING: Bantamweight Luke Campbell won Britain’s first Olympic gold medal in his division since 1908, dramatically knocking down John Joe Nevin, of Ireland, midway through the third round of a 14-11 victory.
RHYTHMIC GYMNASTICS: Russia’s Evgeniya Kanaeva became the first rhythmic gymnast to win two Olympic all-around titles, defending her gold medal from Beijing.