BBC SportOlympics

Sprint showdown
The 100m is fantastic to watch. The buzz around Asafa Powell (left) and Tyson Gay (right) is what athletics is all about - it's box office.

But can Powell run when it matters? Under pressure he's a different athlete.

You see it in his eyes, breathing patterns and he tightens up at the gun. And then a few weeks later he can break the world record!

They're both awesome specimens. Week-in, week-out, I'd back Powell, but in terms of dealing with pressure, you would put the medal around Gay's neck every time.