Felix Sanchez of the Dominican Republic won Olympic gold in the men's 400 meters hurdles on Monday.
Sanchez, the Olympic champion in Athens in 2004, clocked 47.63 to take gold, the exact same result as his personal best of eight years ago.
Michael Tinsley of the United States took a surprise silver in 47.91, while Puerto Rico's Javier Culson, twice world silver medalist, took bronze in 48.10.
Britain's world champion Dai Greene came fourth in 48.24.
On the podium, Sanchez broke down in tears several times.
"No one expected this," he said. "A lot of people said I should retire but I stuck with it. They'll all be celebrating now."
Sanchez dedicated the victory to his grandmother Lillian, who passed away during the Beijing Games.
"I just wanted to make her proud so I've got her name on my spikes," he said. "The day she died in Beijing it broke my heart. That's why I ran with the picture close to my heart."
Tinsley was almost as moved.
"I've been dreaming about this moment since I bought my first pair of spikes. I've put my life into this, I've had to sacrifice so much for this, I'm so proud. I've been running my hardest."
For Culson, the bronze medalist, it was a missed opportunity.
"It was a very bad run on my behalf. I'm not pleased with it at all. I lost my rhythm towards the end of the race and I couldn't get it back. I send my apologies to the people back home but at least I made it to the final."
Home favorite Greene said he was stunned by his failure to medal after such a promising year.
"I think I am tired and shocked. I gave it everything I could. I was just too tired at the end and just missed out on a medal."