NEW YORK — Like a bolt out of nowhere, Usain Bolt is now the world's fastest man.

The Jamaican runner, who doesn't even consider the 100 meters his best race, set the world record tonight with a time of 9.72 seconds at the Reebok Grand Prix, .02 seconds faster than the old record held by his countryman, Asafa Powell.

Bolt was using the 100 for "speed work" and to avoid having to run the more grueling 400, when, suddenly, he ran the world's second-fastest time last month at 9.76. Even then, he said he wasn't sure if he would give up the 400 meters for the 100 for the Beijing Olympics.

Hard to imagine he has any choice now.

Unfurling his lanky frame — listed at 6-foot-4, but probably more like 6-5 and, either way, considered too tall for this kind of speed work — he created a big-time gap between himself and Tyson Gay at about the halfway point, then routed him to the finish line.

Gay, the best sprinter in America, finished in 9.85.

Within moments of crossing the finish line, the 21-year-old from Kingston was hoisting the Jamaican flag and a crowd with hundreds of Jamaican fans was going wild.

"Just coming here, knowing a lot of Jamaicans were here giving me their support, it meant a lot," Bolt said. "I just wanted to give them what they wanted."

But who could have expected this?

Bolt has long been considered one of his country's top, up-and-coming sprinters, but his height and running style seemed to make him much more fit for the 200 and 400.

Like so many who compete in the 100, Bolt had lots of work to do with his push out of the blocks. He doesn't consider himself a true pro at that. And after a bad false start by the field — the second gun didn't go off until the runners were 20 meters down the track — this simply didn't seem like a night for world records.

But it was.

"He ran a perfect race," Gay said. "I've got to take my hat off to him."