LaShawn Merritt of the US satisfied his hunger for success on Tuesday by regaining the 400m title at the world championships while defending champ Kirani James of Grenada faded badly to finish seventh.

Merritt took the race from the gun and went hard over the first 200. He still had plenty left in the tank coming into the home stretch to seal victory in a world-leading 43.74 seconds.

Compatriot Tony McQuay (44.40) made it a 1-2 for the US, which has now won all but four of the men's world titles in the event.

Luguelin Santos of the Dominican Republic edged out Belgium's Jonathan Borlee for bronze in 44.52.

"I've said it many times already: I was hungry ... probably the hungriest person in the field," Merritt said.

"Not only was I starving for a great performance, I was also starving like I didn't eat a lot today, so I was really starving.

"I wanted to go out and put a great race together, I was ready mentally and physically to put a 43 together, and that's what I did."

Merritt, the 2009 champion, held a slight lead as he and James came off the final bend with arms pumping high, but the American seemed to have endless reserves of energy while James went backwards through the field.

"It was poor execution on my end; I need to go back to the drawing board and think again," James told the BBC.

"I didn't come to the world championships expecting this. I just need to move on."

Merritt returned from a 21-month doping suspension in 2011 after a positive test for using an over-the-counter male enhancement product that contained a banned substance.

He then lost his world title to teenage upstart James, whose victory prompted massive street celebrations in his home country.

(China Daily 08/15/2013 page22)