After winning the individual 100m and 200m titles, Bolt's task was made easier when American fourth-leg runner Justin Gatlin fluffed his start, stumbling and veering into the Jamaican's lane. The win rubber-stamped Bolt's place as the most successful athlete in world championship history, taking his all-time tally to eight. That matches American trio Carl Lewis, Michael Johnson and Allyson Felix but the world's fastest man moved ahead by virtue of his two silvers from 2007.
The Jamaican quartet of Nesta Carter, Kemar Bailey-Cole, Nickel Ashmeade and Bolt secured the Caribbean nation a hat-trick of world titles in a time of 37.36.
Gatlin brought home the U.S. in 37.66 with Canada upgraded to bronze after Britain were disqualified, continuing their relay woes of past championships in which they have often failed to get the baton around a full lap.
The Britons were penalised after a changeover mistake between Harry Aikines-Aryeetey and James Ellington who minutes earlier had told the BBC that the team had "got the changeovers down to a tee now".