Irish raider Energumene's defeat in the Clarence House Chase at Cheltenham on Saturday saw one punter lose over €800,000.
The Willie Mullins horse was a warm favourite for the Grade 1 race and attracted plenty of support in the betting market.
This support included single bets of £350,000 at 4-7 and another of £375,000 at 8-15 with bookmakers Star Sports, who revealed the huge bets before the race.