American Kevin Stadler, the world number 256, justified tournament organisers’ decision to invite him to compete by carrying off the Johnnie Walker Classic title in Perth.
The son of 1982 Masters champion Craig Stadler eagled the 18th hole to steal ahead of Australian Nick O’Hern.
His final-day 69 followed rounds of 64, 69 and 66 and made for a 20-under-par aggregate total of 268, earning Stadler a £210,000 cheque, by far the biggest prize of the 26-year-old’s fledgling career.
O’Hern had carded a closing 68 for second place, while sharing third on 16-under 272 were Australians Robert Allenby and Richard Green after final rounds of 66 and 71 respectively.
Korean KJ Choi finished with a 72 for fifth place a further shot back, while England’s Ian Poulter was in a group of three on 14-under.
Poulter carded a 69 and at one stage was only three strokes off the pace before two late bogeys cost him any chance of victory.
Another Englishman, Ross Fisher, shot a final-round 72 to finish 12-under, with Paul Casey one stroke further behind after his one-over-par fourth round.
Poulter climbs to 19th on the European Tour Order of Merit, with Fisher rising to 29th and Casey maintaining fifth place.