Usain Bolt has secured his third gold medal at the 2015 World Athletics Championships, leading Jamaica to the title in the men's 4x100m relay in Beijing.
The United States came onto the finishing straight ahead, but Mike Rodgers and Tyson Gay were slow to complete their changeover, allowing Bolt to sprint clear on the anchor leg.
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The Americans initially recovered to finish second ahead of China, who broke the Asian record in the heats to make the final, but the USA were disqualified shortly after crossing the line because of the mistake with the baton.
The disqualification promoted Canada to the final spot on the podium.
Great Britain, who won bronze two years ago, were unable to finish, failing to complete their final changeover, despite coming out of the final bend in third position.
