Nia Ali of the United States stormed to victory in the 100m hurdles at the world championships here Sunday as Keni Harrison's wait for a major title continued.

Ali surged into the lead after around 50 metres to take gold in a personal best of 12.34sec at the Khalifa Stadium.

But it was more disappointment for Ali's USA team-mate Harrison, the world record holder who is still to win a world or Olympic title.

Harrison took the silver in a time of 12.46sec while Jamaica's Danielle Williams won bronze in 12.47sec.