BERLIN (AP) – Usain Bolt vs. Tyson Gay. Flash vs. “boring.” Triple Olympic champion vs. triple world champion.

This 100-meter showdown could be the defining moment of the world championships, which open with the 100 heats Saturday.

“I’m itching to run,” Bolt said Thursday. “I can’t wait.”

Bolt seemed as relaxed and confident as he was last year when he set three world records on his way to Olympic titles in the 100, 200 and sprint relays in Beijing. By then, Gay’s season was ruined by injury. Now, both say they are at their peak, convinced the winner will likely set a world record Sunday.

“He’s already shown the world what he can do, but I haven’t shown all my talents yet,” Gay said as both sprinters held competing news conferences that underlined Bolt’s showmanship as much as Gay’s seriousness.

At the Yaam Beach Club on the Spree river in Berlin, the reggae was blaring, the bamboo bar was moving drinks and Bolt was promising to produce a new dance act if he wins the world title at Olympic Stadium.

As a joke, he had two rubber arms attached to his back already making the iconic bow-and-arrow move when he came into the sweltering, body-packed news conference.

“I set a standard for myself. I have to live up to it,” he said.

Off the track, that means flash and glitz. On the track, the standard is 9.69 seconds over 100 meters.

“I am always ready to compete at my best,” he said.

In Beijing, he was already showboating well before the finish line and still set the world record. This time, a thriving Gay could make it a lot tougher.

Gay already won the 100 and 200 at the 2007 worlds in Osaka, Japan, and helped the U.S. team capture the relay gold to be a triple champion. At the time, Bolt was known to few but the true track aficionados internationally and the raucous fans back home in Jamaica.

Now, he has dwarfed everyone on the track.

“Personally, I mean he’s a great athlete. He’s an entertainer and he’s setting the world on fire right now. He’s the guy to beat and that’s my job,” Gay said in a much more low-key setting in an international hotel a few miles down the river.

“I’m what you’d probably call boring,” Gay said. “He is very entertaining, very funny.”

It could almost be forgotten that it is actually Gay who is the top performer in both the 100 and 200 this season.

Gay’s 9.77 in Rome last month beats Bolt’s 9.79 in Paris. In the 200, Gay has 19.58 from New York in spring, just 0.01 faster than Bolt’s mark in Lausanne, Switzerland. The edge, though, means precious little because Gay set his times in good conditions and Bolt faced rain and wind in his top races.

They have not raced each other this year, although they did cross paths in the office of a Munich doctor.

“Physically, I’m OK,” said Gay, who skipped a practice meet over the weekend.

Bolt injured his foot in a car crash this year but feel in top shape, too.

In a moment of humility, Bolt readily acknowledged that victory is not assured.

“No one can predict the podium. I can hope I’m on top,” he said.

Asked whether he had even considered losing, he said “there is always a possibility.”

For Gay, there is an element of revenge after the United States failed to win a single sprint title in Beijing, while Jamaicans took five of six golds.

“When we have American pride we don’t want to let America down by not bringing home as many medals as we think we should,” Gay said. “So we all want to, I guess you could say, redeem ourselves and show our true talents. I believe we will do so.”