The 10-meter platform was supposed to be another showdown between Olympic champion Matthew Mitcham and the powerful Chinese.

Tom Daley knocked 'em all off.

The 15-year-old British diver barely rippled the water on his final attempt, then claimed the gold when Mitcham and Qiu Bo botched their last dives at the world championships on Tuesday.

Daley is the youngest diver to win a world title in men's platform. Qiu held on for the silver; Mitcham didn't even when a medal, slipping to fourth behind another Chinese diver, Zhou Luxin.

The only American in the 12-man final, David Boudia, finished sixth.

"I can't believe what I've done today," Daley said. "I really didn't think I would win this competition."

Everyone pegged this as a showdown at the Foro Italico between Mitcham, who won gold at the Beijing Games, and a Chinese team intent on getting back at the Australian diver who cost the home team a sweep of all eight diving golds last summer.

Qiu was ahead going to the final dive, just ahead of Mitcham. Daley's main goal, it seemed, was holding off Zhou for the bronze.

But Daley, going with a less difficult dive than nearly everyone else in the final round, performed the reverse 3 1/2-somersault with a tuck to perfection _ his body whirling like the wheels of a Ferrari before he popped out at just the right time, looking as though he had disappeared without touching the surface.

He popped up with a big smile, and was really grinning when he saw the scores: three perfect 10s, the rest 9.5s.

But Mitcham and Bo were still to come, and both were performing a backward 2 1/2 pike somersault with 2 1/2 twists. It has a higher degree of difficulty (3.8 vs. 3.4) than Daley's dive, which meant both had a chance to score more points with similar scores.

Neither came close to matching the teenager.

Mitcham over-rotated his landing, making a huge splash. He buried his head in his hands after climbing out of the water, fully aware his chance to win another gold was gone.

"I didn't quite save," he said. "Sometimes you can save dives that are a bit over, and I really tried to fight for it, but I still kicked up a little bit of water."

Bo was the last to dive. He, too, kicked out a little too soon, his legs carrying past the crucial point for entry. Another big splash.

His coach, watching from the deck, dropped his head. When Bo got out of the pool, he bent over in anguish, the coach coming over to pat him on the back.

"I really thought they were going to get it, because they only needed 7.5s and 8s," Daley said. "For them not to get it is just crazy."

Daley finished with 539.85 points, the first British diver to win a world championship. The country has never won an Olympic gold medal, which will surely put Daley under intense scrutiny leading up to the 2012 London Games.

He's ready for it.

"I really hope that I could do this again, because the feeling I've got right now is just incredible," he said. "I want it to carry on forever."

Qiu finished second with 532.20, while Zhou edged Mitcham for the bronze, 530.55 to 529.50.

"It's so competitive that even the tiniest little mistake puts you out of medal contention," Mitcham said. "I was only like one point out _ with the mistake."

Mitcham is looking forward to getting another shot at Daley in London.

"The UK already love him," the Aussie said. "They already know that he's their little champion, and they already know that he's going to be their biggest medal hope for London. I hope to be right up there with him."

Boudia scored 10s on two of his dives, but a slip-up on his 3 1/2-somersault with a tuck cost him a shot at a medal. Still, it was the best U.S. finish in the event at worlds since Mark Ruiz placed sixth in 1998.

"I felt comfortable up there, and I started off well," Boudia said. "I had a mishap on my gainer and gave up some points there, but it happens. There's room for improvement."