Teeth clenched, Usain Bolt grimaced as he churned toward the finish line, hoping to coax a fraction more out of his 6-foot-5 frame.

The big, yellow numbers flashing another world record time, told the Jamaican sprinter he had gotten what he wanted out of the 200 meters Thursday at the world championships.

Beyond the mark of 19.19 seconds, though, was something else -the fact that he is altering his sport.

For the second straight race - five, if his record-breaking runs at the Beijing Olympics are counted - Bolt's biggest competitor was the clock. He bettered his old world record by a whopping .11 seconds, the same margin he shaved off the 100 four days earlier, when he finished in 9.58.

"I'm on my way to being a legend," Bolt said, without a trace of arrogance.

No debate there.

He is erasing chunks of time from records that normally take years to break. He is beating the so-called competition by body lengths - this time, Alonso Edward of Panama was 0.62 seconds behind - in a sport often decided by photo finishes.

"He's a gift to this earth," said American sprinter ShawnCrawford, who finished fourth. "He's a blessing to the track game.... I'm just waiting for the lights to flash 'game over,' 'cause I felt like I was in a video game."

Bolt can't be caught, even when he gives away tips. Just before the start of the race, Bolt told good friend Wallace Spearmon to stay close to him on the curve and follow him home. The American tried.

"Even if I run the best turn of my life, I'm still going to be behind," said Spearmon, who finished with the bronze. "I knew what was in store for the race. I expected it to be at least that fast."

When he saw his record time, Bolt pointed at the display, thenstuck out his tongue in his best Michael Jordan impersonation.

"Even us in the field, we think there is going to be somethingphenomenal from him," Crawford said.

Bolt feeds off the energy from the crowd. The louder they get, the more playful he becomes.

He showed up at the start wearing a T-shirt with a new take on President Kennedy's famous Cold War quote "Ich bin ein Berliner."

This time, the slogan said, "Ich bin ein Berlino," a reference to the bear mascot of the championships.

The audience ate it up, along with Bolt's hand gestures and other assorted antics.

Then it was time to go to work in his yam-colored Pumas. He jetted out of the blocks, turned the corner and it was over.

No one was going to catch him once he reached the straightaway. "I was surprised with myself that I did so well," Bolt said.

After that, came his favorite part - the celebration. He involved just about everyone as he made his way around the track, stopping to sign autographs for kids, mugging for pictures and posing with Berlino, who joined Bolt in the sprinter's signature bow-and-arrow stance.

Midway around the track, Bolt took of his shoes and carried them.

"I was so tight, I couldn't even really jog. I was just tired," said Bolt, who celebrates his 23rd birthday Friday.

So how low can Bolt go? Even he has no clue.

"I keep saying anything's possible as long as you put your mind to it," he said.

Former sprint star Michael Johnson, whose record of 19.32 stood for 12 years before Bolt broke it last year, believes the 19-second barrier might be next.

"He could," Johnson said. "He's very tall and has an extremely long stride. He's not the only person in the world that's 6-foot-5, he's just the only one that's 6-5 and that fast."