Australia's Commonwealth champion Jana Pittman scored a stunning upset victory in the final of the women's 400m hurdles.

The 20-year-old ran down world record holder Yuliya Pechonkina 15m from the finishing line with the Russian eventually struggling home in third place.

Racing out of the final bend, Pechonkina, who set her world mark of 52.34sec earlier this month, looked to be well in control with a five-metre lead despite having struck one of the early hurdles.

But Pechonkina tied-up badly off the last hurdle and Pittman, who had run a more even pace, seized her chance.

With the distressed favourite starting to stagger, the Aussie youngster swept past her to win in 53.22sec, holding off the challenge of American Sandra Glover who ran a season's best 53.65 to claim the silver medal.

Pechonkina, who has suffered ill-health all season, clocked 53.71.

"I've had my ups and downs throughout the season," said Pittman, "but I managed to find some consistency and energy at the right moment."

Expecting a fast start from the favourite, Pittman said: "I was concentrating on my own race and I knew it had to be a tactical race.

"I also knew that Pechonkina was going to be far ahead of us all at 200m - but I noticed at the ninth hurdle she was within my reach."

Refusing to blame her tactics, Pechonkina said: "The race felt sort of heavy. In the end my legs just gave up."