Gay & 200m world champion Allyson Felix were in London on Thursday

Gay eclipsed the Jamaican by winning 100m, 200m and 4x100m relay gold at the World Championships, but Powell set a new 100m world mark earlier this month.

"I'm not going to step up to the plate and race him when I'm not 100% because right now Asafa's on fire," he said.

"I thought I had an edge after the Worlds (in Osaka), but then he ran 9.74 in Italy and now he probably thinks he's got a mental edge."

Gay was speaking in London at the announcement of a �100m sponsorship deal between Adidas and the London 2012 Olympic Committee.

"I won't race Powell this year, but more than likely will before the Olympics (in Beijing next year)... depending on if we're both healthy, there will be a big match-up.

"I'm tired now mentally but looking forward to refocusing for the next couple of meets," said the American. "Next year when I'm running 9.7s it will be even more exciting."