American Kerron Clement stormed to a surprise gold in the men's 400 metres hurdles at the World Championships in Osaka on Tuesday.
The 21-year-old ran a superb last 200 metres, clocking the year's quickest time of 47.61 seconds with Olympic champion Felix Sanchez taking silver for the Dominican Republic in 48.01.
Poland's Marek Plawgo claimed bronze in 48.12 with pre-race favourite James Carter fading badly over the final 150 metres to finish a disappointing fourth in 48.40.
"I'mjust really, really thankful to come to Osaka and beat the best," Clement told reporters. "I came away from Helsinki in 2005 without a medal but I've matured a lot and learned to run through the line."
Carterhad finished second to fellow American Bershawn Jackson at the last world championships in Finland.
Jackson failed to qualify for the final in Osaka after clipping the last hurdle in Sunday's semi-finals.