Wednesday, 8 August 2012: Pearson starts at $1.21 and scrapes home ahead of Harper at $9.40

The margin was a miniscule 0.02 seconds but it was more than enough to satisfy the legion of Betfair punters who took short odds for Australia's Sally Pearson to win the Olympic 100m hurdles gold medal this morning.

A resounding favourite to claim her first Olympic gold medal for seemingly an eternity, the weight of expectation didn't halt Pearson, nor did it deter the backers from around the world from plunging on the Aussie who started the final at the rock bottom odds of $1.21.

The weight of money for Sally is reflected in the huge market move in her favour; she was trading at $1.55 prior to the heats before shortening to a low price of $1.19 just seconds before the start of the final.

It took just 12.35sec to run the race but that was ample time for some feverish in-play trading to occur on the Betfair exchange.

Under siege from a rampant Harper, layers offered a top price of $1.93 for Pearson to win mid-race, while the American traded down to $2.32.

Betfair's Mathew Thompson said: “Sally's much anticipated gold medal has made getting out of bed on a wintery morning significantly easier today. Punters on Betfair could have taken $1.55 for the mighty Australian to win gold in the 100m hurdles only days ago and they'd have been pleased to see her head to the start at $1.21.

“It was a clinical display by Pearson in Olympic record time, which made the $1.93 available to in-play punters all the more attractive.”