World champion Sally Pearson edged an American trio to claim 100 metres hurdles Olympic gold for Australia at the London Games on Tuesday.

Pearson broke down on the track in tears of delight and disbelief when victory with a 2012 world best of 12.35 seconds was confirmed.

The 2008 gold medallist Dawn Harper got silver in 12.37, Kellie Wells took bronze in 12.48 while Lolo Jones missed the podium in 12.58.