BEIJING,(Reuters) - Jamaica's Danielle Williams won the world championship 100 meters hurdles gold as her more experienced rivals crumbled under pressure on Friday.
She took the lead after the last flight, winning in a personal best 12.57 seconds ahead of Germany's Cindy Roleder who also clocked a best time of 12.59.
Bronze went to Aline Talay in a Belarus record 12.66.
Danielle, 23, raced in the final alongside her 25-year-old sister Shermaine who finished seventh in 12.95.
It was the first time since the championships began in 1983 that two siblings had competed together in a final.
Two of the leading American hopes, Dawn Harper Nelson and Keni Harrison, were eliminated at the semi-final stage.
Harper Nelson fell and Harrison was disqualified for a false start.
In the final, 2013 world champion Brianna Rollins all but wrote off her chances by knocking down the first hurdle.
The American rallied but could do no better than fourth place in 12.67, passing Britain's Tiffany Porter who led to the eighth flight before folding.
"I was just hoping I finished with a medal, I wasn't sure where I finished, I knew it was close," Danielle Williams told reporters. "I was just looking up at the screen waiting for the results to come up."
Roleder, 26, regards herself as a heptathlete and was not even ranked in the world's top 20 as a 100 hurdler going into the Beijing championships.
"That rocked," she said. "I am super happy. I cannot believe what happened.
"After the semi-final I was gobsmacked for a little while but our physio Thomas Ring set me up again and my coach Wolfgang Kuehne also made me strong mentally."
Writing by Steven Downes; Editing by Tony Jimenez