Pearson wins Australia's first track gold

World champion Sally Pearson won the women's 100 metres hurdles in a blanket finish to give Australia their first gold medal in athletics at the London Olympics.

The dominant sprint hurdler of the last two years, Pearson led from the start but Americans Dawn Harper and Kellie Wells pushed her all the way before the Australian crossed the line in 12.35 seconds, an Olympic record.

Defending champion Harper took silver in 12.37 and Wells won bronze in 12.48, both athletes running personal bests.

The 25-year-old Pearson faced a nervous wait before her name flashed up on the scoreboard and she collapsed on the track in delight when her victory was confirmed.