LaShawn Merritt performed the "Virginia Shuffle" before storming down the final 100 metres to overhaul his Jamaican and South African rivals and win the world 4x400 metres relay title for the United States.
The Americans have crossed the line first in the last 10 world championships, although four of those victories were retroactively annulled for doping offences, but their grip on it looked in grave doubt at the final bend.
The Americans had trailed in third place for much of the previous 1,500 metres but Merritt, who lost his 400 title earlier in the week, found his way around his rivals to retain the title in two minutes 59.31 seconds.
Merritt, who returned at the end of July after a 21-month doping ban, said he was disappointing that schedule changes meant that the relay no longer took place on the last night of the championships.
South Africa, who had dropped double amputee Oscar Pistorius for the final, finished with the silver medal when L.J. Van Zyl crossed the line in 2.59.87.
Jamaica's anchor Leford Green finished a nose behind the South African in 3.00.10 to claim the bronze medal.