Rising American talent Jordan Spieth shot the round of his life for an eight-under-par 63 as his rivals laboured in the Sydney wind to claim his second professional title by six strokes at the Australian Open.
The Texan, who shared second place on his US Masters debut in April, fired eight birdies in a flawless final round to secure the Stonehaven Cup at 13-under 271 for the tournament at The Australian Golf Club.
The $1.06 million tournament had been billed as a duel between world number one Rory McIlroy and number three Adam Scott but 21-year-old Spieth stole the show with his stunning final round.
The world number 14 was the youngest Australian Open champion since Aaron Baddeley won his second title as a teenager in 2000 and the first American since Brad Faxon in 1993, when Spieth was just a few months old.
"I didn't think the round was out there but the putts just kept going in," Spieth said in the greenside presentation. "It's the best round I've ever played, the best win I've ever had, it's pretty awesome."
Australian Rod Pampling hit a 68 for second place, a shot better than compatriot Brad Rumford (70) in third with another local Greg Chalmers (71) in fourth on five-under. All three secured berths at next year's British Open at St Andrews.
Scott (71) was fifth on four under, while defending champion McIlroy, whose victory at the Royal Sydney last year provided a springboard for his stellar 2014, finished 15 shots off the pace in a share of 15th after a 72.