Nigeria’s Tobi Amusan broke the women’s 100 metres hurdles world record in a stunning semi-final effort at the World Championships on Sunday.

The record time of 12.12 seconds broke Kendra Harrison’s mark of 12.20, as the American finished second in the heat.

While most athletes aim to conserve their energy in the semi-final, the 25-year-old Amusan held nothing back at Hayward field, a day after she set the African record in the opening heats.

“It is a strong feeling. I wanted to get out and go,” she told reporters. “I did what I had to do. Looking forward to the finals.”

She shocked the crowd at Eugene, Oregon, putting on the kind of superb performance usually reserved for prime time in the opening race of the Sunday evening schedule.

Jamaican Britany Anderson won her semi-final in a national record 12.31 seconds, with Puerto Rico’s Jasmine Camacho-Quinn also advancing (12.32).

“It is a strong feeling. I wanted to get out and go,” she told reporters. “I did what I had to do. Looking forward to the finals.”

She shocked the crowd at Eugene, Oregon, putting on the kind of superb performance usually reserved for prime time in the opening race of the Sunday evening schedule.

Jamaican Britany Anderson won her semi-final in a national record 12.31 seconds, with Puerto Rico’s Jasmine Camacho-Quinn also advancing (12.32).