OSAKA, Japan (Reuters) - American Tyson Gay was hoping to complete a sprint treble at the world athletics championships early this morning Bermuda time as the men's 4x100 metres relay takes centre stage.

The 24-year-old beat world record holder Asafa Powell in the 100 metres on Sunday and scorched to victory in the 200m final on Thursday to become the third man to win both sprint titles at a world championships after Maurice Greene and Justin Gatlin.

The 200 metres final was the eighth race in six days for Gay in the sauna-like atmosphere of the Nagai Stadium but he showed no sign of fatigue or the hamstring problem that had troubled him in the heats.

Following that victory, though, he said he had been shattered and did not run in the relay heats in which the American quartet posted the second fastest time behind the Jamaicans, who were anchored by Powell.

"I am extremely tired," he told reporters. "I couldn't think of nothing, couldn't put my arms up to celebrate, couldn't really jog on my victory lap. I don't think I am going to run the prelims (of the relay) unless they need me."

Jamaica's Veronica Campbell cannot complete a sprint treble of her own having been beaten into silver by Allyson Felix in the 200m on Friday.

However, the 100m champion will be looking to double her gold tally with a win in the women's 4x100 relay.