LONDON (AP) - Aries Merritt led a 1-2 finish for the United States in the Olympic 110-meter hurdles, winning in 12.92 seconds Wednesday night. Defending champion Dayron Robles of Cuba pulled up midway through and clutched his right hamstring.

Jason Richardson, the world champion, was second in 13.04. Hansle Parchment of Jamaica took the bronze in 13.12.

Merritt has been the fastest hurdler in the world for most of 2012 and backed it up with his performance in London. The former University of Tennessee standout recorded the fastest time in both the prelims and the semifinals ahead of a personal best run in the final.

Merritt's gold medal-winning time bested his previous personal best by .01 and was also the fastest time in the world this yer.

Merritt has been the world's fastest hurdler in 2012, and that did not change here in London. He had the fastest time in round one Tuesday morning then backed it up with the fastest time in the semifinals early Thursday evening. He finished the job later that night. His time of 12.92 was his personal best by .01 and the fastest time of the year in the world.

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.

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