BERLIN  Usain Bolt isn't just rewriting the record books; he's redefining what the human body can do.

LOOKING AHEAD: Bolt says 200 may not bring record time

Bolt became the first man to run 100 meters in under 9.6 seconds and still left people wondering how fast he can go.

Bolt clocked 9.58 seconds Sunday night, smashing the world record of 9.69 he set at the 2008 Beijing Olympics. He won his first IAAF world championships title in the same stadium where Jesse Owens won four gold medals at the 1936 Olympics.

"I don't think I'm in Beijing shape, but I think I'm in very good shape," said Bolt, who was in a car accident earlier this year that took away from his training.

Tyson Gay did his part in the highly anticipated showdown, but was overshadowed by the ebullient 6-5 Jamaican.

Gay, who is 5-11 and wore the U.S. team's "JO" patch honoring Owens on his singlet, set an American record of 9.71. He eclipsed his own mark of 9.77.

"I'm really happy that Usain Bolt broke the record," said Gay, the second-fastest human ever. "I know that may sound strange, but I knew it was humanly possible for somebody to run that fast. Unfortunately, it wasn't me."

Gay, who has a groin injury he says is "barely hanging on," will speak to doctors and determine whether he will try to fend off Bolt in the 200, starting Tuesday.

Asafa Powell, the former world recordholder from Jamaica, was third in 9.84.

Bolt took command of the race at about 40 meters.

"He was gone, disappearing," said Dwain Chambers of Britain, who was sixth in 10.0.

Chambers expects the world record to fall again next year. "The kid's on fire."

Bolt, who will turn 23 Friday, clipped more time off an existing 100-meter world record than anyone since electronic timing was introduced in 1968.

"I think 9.5 is definitely a big thing," Bolt said. "I'm feeling proud."

Clowning around at the start of the 100-meter final Sunday, Bolt covered his mouth with his hand, then removed it to reveal a wide grin. He licked his fingers before smoothing his eyebrows, blew a kiss and nodded vigorously as the public address announcer in the IAAF world championships introduced him.

But unlike Beijing, where Bolt eased up and showboated at the finish of the 100 final, he bulldozed across the line for a world record.

Bolt did sneak a peek on each side, but no one was within his orbit. And he struck his "lightning" pose after the race as fans waved their yellow foam "Bolt Arms" at him.

"I can have all the fun I want before the race," the playful Jamaican said. "When the starter says, 'On your mark,' I refocus, and then it's time to go. I know what I have to do, so there's no worries."

And he did it. With his long stride and quick turnover, Bolt is the perfect example of the way a sprinter should perform.

He got off to a good start — a part of his race he has worked to improve — and took the lead at about 40 meters. "When I got to the 50," Bolt said, "I knew it was going to be hard for anyone to get past me."

Bolt has said his goal is to be a living legend.

"I think it's getting there," he said, "but for me, I don't think two seasons can do it. I think I have to do it year after year. I have to do a lot of hard work, because these guys are going to be coming."

Gay, whose showdowns with Bolt had been dubbed as the "Grosse Duelle" on Berlin billboards, might not get a chance for revenge in the 200. Gay, who won the 100 and 200 in the 2007 world championships, has been hampered by a groin injury that might require surgery after the season. The 200 rounds start Tuesday.

"There's some pain right now, and see how it goes tonight," Gay said.

Bolt isn't predicting a world record in the 200. "I'm going at it to run hard," he said, "but I think it's going to be more difficult because I just took Tyson's 100-meter championship. He's not going to be smiling at me for the 200 meters.

"It's going to be all fun."

The women's 100 is also shaping up as a USA-Jamaica duel. Kerron Stewart, the 2008 Olympic silver medalist from Jamaica who ran for Auburn University, had the leading time of 10.92 seconds after the second round.

"This is all I can do: You either give everything or nothing at all," Stewart said.

Carmelita Jeter, the U.S. champion, was next (10.94), followed by two Jamaicans, defending champion Veronica Campbell-Brown (10.99) and Shelly-Ann Fraser (11.02.). The other two Americans, Lauryn Williams, who ran 11.06, and Muna Lee, who ran 11.13, each had season bests. The final is Monday. (TV: 1-4 p.m. ET, Versus)

In the women's 400, Sanya Richards will have to beat her top rival three times in four days to win her first individual world title.

In a rare draw, Richards, the five-time U.S. champ, and Britain's Christine Ohuruogu, the Olympic gold medalist, found themselves in the same heat Saturday. They raced again in the semifinals, with Richards winning both. The final is Tuesday.

Richards suffers from Behcet's Syndrome, an inflammation of the blood vessels which she said has flared up while she's been in Berlin.

"They say stress brings it on," Richards said. "It doesn't get more stressful than this, but I feel fine."

Christian Cantwell won the first medal for the USA on Saturday. Cantwell beat Olympic champion Tomasz Majewski of Poland for gold in the shot put.

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