Jamaica won the Olympic gold medal in the men's athletics 4x100m relay on Saturday.
Nesta Carter, Michael Frater, Yohan Blake and Usain Bolt set a world record time of 36.84 seconds.
It was Bolt's third gold medal at the Olympic stadium in London.
The United States won silver.
Canada finished third, but were disqualified, leaving Trinidad & Tobago to claim bronze.
Bolt has won the 100m, 200m and 4x100m relay titles at the London Games, as in Beijing four years ago. He is the only athlete to accomplish this.
Earlier, the United States won the women's 4x400 metres relay for the sixth successive Olympics.
Allyson Felix, who ran the second leg, won her third gold medal.
Russia won the silver and Jamaica won the bronze.
