LONDON -- Aries Merritt's hurdling career started on a dare. It took off with a technical change. And it peaked with a gold medal Wednesday night.

The 27-year-old Merritt led a 1-2 finish for the United States in the 110-meter hurdles at the London Olympics, winning in 12.92 seconds. World champion Jason Richardson was second in 13.04. Hansle Parchment of Jamaica took the bronze in 13.12.

Defending champion Dayron Robles of Cuba pulled up midway through the race, clutching his right hamstring.

Merritt and Richardson gave the U.S. its first gold-silver finish in the event since 1996, when Allen Johnson and Mark Crear claimed the top two spots in Atlanta. No American had won gold since.

"I've worked so hard for this moment and who knows if I'll ever get this chance again?" Merritt said. "It's a once-in-a-lifetime moment and I'm just kind of living it. I'm the champion. It still hasn't sunk in yet that I'm Olympic champion. I'm still in shock."

He should have seen it coming.

Everyone else did, even his high school track coach about a dozen years ago.

At the end of Merritt's freshman year at Wheeler High in Marietta, Ga., teammate and 2008 Olympian Reggie Witherspoon challenged him to jump a fence before practice. They didn't think anyone was watching.

"It was just a random dare," Merritt recalled. "We got there kind of early from class. He said, 'I bet you won't jump that fence.' I was like, 'I can jump that fence.' He was like, 'Nah, you ain't jumping it. You ain't jumping it.' I was like, 'All right.'"

Merritt then ran up and cleared the fence, with his coach watching nearby.

"He was like, 'You're going to be a hurdler now,'" Merritt recalled. "That's pretty much how it started."

His coach, Chad Walker, clearly spotted something. Maybe it was the long strides. Maybe it was the smooth approach. Maybe it was the graceful leaping ability. Whatever the case, it eventually turned into Olympic gold.

Merritt broke the 14-second mark as a senior, got a full scholarship to Tennessee and set several school and Southeastern Conference records.

He thought his Olympic moment would come in Beijing in 2008, but his grandmother died before the U.S. trials and he carried the heartbreak with him for some time. Making things worse, he pulled a hamstring and missed months of training. He finished fourth in those Summer Games.

"If you're not emotionally stable, you're not going to (win)," he said. "To wind up in fourth place was a blessing."

Four years later, Merritt was on top of his game.

He credits the ascent to a change with his start, a minor tweak that most outsiders would never even notice. He reduced his number of strides from eight to seven between the starting line and the first hurdle, a move that many elite hurdlers already had adopted.

One less step, one giant leap.

And now a gold medal.

"It means everything to me," said Merritt, the world indoor champ. "I'm just happy that it's finally over. To be able to execute on the biggest stage in track and field is nothing short of amazing. I've proven myself, finally, on the biggest stage of my life. I can't be more thrilled."

Richardson, meanwhile, was somewhat disappointed with second.

But after cooling off, it started to sink in that Richardson has two medals in two major events – one at the world championships and another in London.

"I'm extremely blessed to say I made two teams and medaled twice," Richardson said. "I'm 2 for 2."

The American duo may have aided by injuries to key rivals.

Robles, the world-record holder, began limping early and came to a stop after clearing the sixth hurdle, then shoved another barrier down to the track.

The 2004 Olympic champion, Liu Xiang of China, got injured in the first round of qualifying and stopped before reaching the first hurdle.

"You never want to think about falling or someone having a mistake," Merritt said. "You just want to focus on executing your race to the best of your ability because you can only control what you do. You can't control what anyone else does."

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