Usain Bolt won his sixth Olympic gold medal, running the anchor leg for a Jamaican team that set the world record in the men's 400-meter relay.
For a second straight Summer Games, Bolt has claimed three gold medals, repeating the formula from four years ago in Beijing that saw him win the individual 100 and 200m races and 400m relay.
The United States, which hasn't won the 400m relay since the 2000 Sydney Games, settled for silver. It was a marked improvement from 2008, when the Americans failed to medal after dropping the baton on the final handoff.
Although Canada was next to cross the line, Trinidad and Tobago wound up taking bronze after it was ruled that the Canadians made an illegal handoff on the last exchange.
Yohan Blake, silver medalist to Bolt in both the 100 and 200 here in London, handed the baton to his compatriot with a lead and Jamaica's national hero finished off the record run by crossing the line at 36.84 seconds. The Jamaicans broke their own world mark of 37.04 seconds set last year.
Bolt also ran the last leg in Beijing to help Jamaica won its first gold in the 400m relay.
Ryan Bailey ran anchor for the Americans and finished .20 seconds behind Bolt.
The American team also included Trell Kimmons, Justin Gatlin and Tyson Gay, who was part of the baton drop four years ago in Beijing.
Trinidad and Tobago posted a time of 38.12 seconds for the bronze.