Online bookmaker Sportsbet Australia has refunded more than $200,000 to punters who backed Chris Waller's Opinion in Race 3 at Flemington after jockey Nash Rawiller lost control of the horse's irons at the beginning of the race.

“Opinion was clearly the best backed horse in the race, but he never stood a chance and refunding punters' bets is the right thing to do,” sportsbet.com.au's Haydn Lane said.