LaShawn Merritt performed the Virginia Shuffle before storming down the final 100 meters to overhaul his Jamaican and South African rivals and win the world 4x400 meters relay title for the United States on Friday.

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 meters 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.

I was third with a hundred to go, I was boxed in, Merrit said. So I did a quick step, I call it the Virginia Shuffle and then I said 'bring it home for the U.S.A.

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.

We like to close the show, he said. But it was another victory and another gold for the U.S.

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.

We had an agreement before the first round that the slowest person would not run in the final and unfortunately that was Oscar, he said.

Jamaica's anchor Leford Green finished a nose behind the South African in 3.00.10 to claim the bronze medal.

I understand the job I had, the guys I was running up against so my job was pretty simple: just keep us in the medals, Green said. I know they were coming. I am not a good runner in front but I gave it my best shot.