The Bahamas took gold in the men's 4x400 metres relay final after overhauling favourites the United States in a thrilling final leg.
Chris Brown, Demetrius Pinder, Michael Mathieu and Ramon Miller sped home in a Bahamian record time of 2 minutes 56.72 seconds, Miller passing American Angelo Taylor with just 50 metres to go.
Bryshon Nellum, Joshua Mance, Tony McQuay and Taylor claimed silver for the US with a season's best time of 2:57.05, ending a run of seven successive golds in the event.
The Bahamas finished second behind the US in Beijing four years ago.
Trinidad and Tobago's Lalonde Gordon, Jarrin Solomon, Ade Alleyne-Forte and Deon Lendore won the bronze with hosts Britain fourth.