Great Britain's Tiffany Porter run out of medals as Williams claims 100m hurdles gold

Porter, who had looked so impressive in the semi-finals earlier in the day, was considered a strong hope for gold – having claimed bronze in the same event in Berlin two years ago. But she was outlasted by Williams, who won in a time of 12.57 seconds, with Germany’s Cindy Roleder storming through to claim silver and Belarus’s Alina Talay in third.

A disappointing hour for Great British athletes was rounded out by Porter, who was firmly in the hunt for victory over the first eight hurdles but just seemed to overextend herself slightly over the final couple of flights, unable to hold off her rivals as she strained desperately for the line – even falling head over heels just after she had done so.

“I’m in one piece. I’m healthy and I made it through the final," Porter said afterwards. “It’s disappointing, I’m very disappointed. It’s unfortunate, but congrats to the ladies who medalled.

“As a competitor you go out to do your best. I gave my all, tried my best, it didn’t happen. I have to congratulate those who medalled.

“It wasn’t a good race, I made a lot of mistakes, I’m just really disappointed.”

Williams, 23, was racing in the final with her 25-year-old sister Shermaine, who finished seventh. Defending champion Brianna Rollins all but wrote off her chances of gold after knocking down the first hurdle in the final. The American rallied but could do no better than fourth (12.67) - coming past Porter at the end.

Earlier on Friday two of the leading American hopes for gold, Dawn Harper-Nelson and Keni Harrison, were eliminated in the semi-finals. Harper-Nelson fell, while Harrison was disqualified for a false start.

Elsewhere in the evening, British sprinter Dina Asher-Smith finished fifth in the 200m final – while Shara Proctor was beaten out for victory in the long jump by Tianna Bartoletta, despite setting a new British record of 7.07m.