LONDON: 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.

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.