Sixteen-year-old Chinese swimmer Ye Shiwen powered down the final length to win Olympic gold in the women's 400 meter individual medley Saturday and smash the world record.

Ye, who burst onto the scene last year by winning world championship gold in the 200 meter event in Shanghai, propelled herself away from American world champion Elizabeth Beisel and to victory.

She posted a time of 4 minutes, 28.43 seconds, just over a full second faster than Stephanie Rice's world record, set in Beijing four years ago.

Beisel looked to have established a solid lead going into the final lengths, but Ye came out of nowhere with 75 meters to go and never looked back, finishing almost three seconds ahead.

Li Xuanxu took the bronze a further second and a half back.

Local favorite Hannah Miley, who took the silver in the same event in Shanghai, was a disappointing fifth.