Australian 100m hurdler Sally Pearson is confident of a gold medal in the London Olympics, despite suffering defeat just three weeks ago.

Pearson is one of the hottest favourites for a gold in any track event, but did suffer just her second defeat in two years against Kellie Wells at Crystal Palace.

The reigning world champion is sure that she will perform better in the Olympics.

"It was not a wake up call," said Pearson.

"It was just not a good race. I only lost by two hundredths of a second.

"If they only beat me by that much on a bad day, I feel sorry for them when I am on a good day."

The 25-year-old has run the three fastest times in the world this year, and her personal best of 12.28s is just 0.07s off Yordanka Donkova's 24-year world record.

"I am capable of breaking it," she said. "It's a matter of where and when I do that.

"My personal best is so much faster than anyone else's in the race so they have the catching up to do."

The women's 100m hurdles gets underway on Monday, with the final taking place on Tuesday evening.