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Video - Robles strides to hurdles gold
World record holder Dayron Robles lived up to his pre-race billing by storming to victory in the men's 110m hurdles.
The 21-year-old Cuban led throughout to win in 12.93 seconds and mark his first Olympics with a gold medal.
David Payne and David Oliver, both of the US, trailed by some distance but took silver and bronze respectively.
Robles came into the final as favourite after the withdrawal through injury of defending champion Liu Xiang of China and America's Terrence Trammell.
"It's disappointing Liu was not able to be here in the final, but I'm sure he will come back and we will have a really good rivalry next year in the world championships," he said.
Oliver remains the only man to have beaten Robles this season, but neither he nor Payne came close to challenging for gold.
Robles showed no nerves and led the race from the moment he rose from the blocks, making the absence of defending champion Liu and two-time silver medallist Trammell even more marked.
I've learned a lot over the past couple of years, and my technique has improved significantly
The bespectacled hurdler sailed over the barriers and eased over the line, while Oliver was forced to withstand a challenge from France's 2005 world champion Ladji Doucoure to secure his consolation bronze.
"I feel very good, I feel complete, everything was good. I'm ecstatic that I am Olympic champion. It has always been my dream," said Robles, who ran a near-perfect race.
"I've learned a lot over the past couple of years, and my technique has improved significantly...from the beginning to the end, it was fantastic technically."
Runner-up Payne described Robles as a "phenomenon" but was happy to add a silver medal to his bronze from last year's world championships.
"I wasn't 100percent this year. I had a lot of setbacks. I wanted to stay up with Robles but he left us behind. He's amazing and could not be stopped."
Payne added, however: "One day very soon, I'm going to go with him and hopefully beat him."