Sydney - Rising American star Jordan Spieth dominated the final round to win the Australian Open by six shots and leave world number one Rory McIlroy and third-ranked Adam Scott floundering in his wake on Sunday.
Spieth carded a sizzling new course record of eight-under par 63 to finish the A$1.25 million OneAsia co-sanctioned tournament at 13-under 271.
It was 21-year-old Texan's second tournament win after last year's John Deere Classic in Illinois.
Spieth was runner-up at the Masters last April behind fellow American Bubba Watson, just missing out on being the first Masters rookie to win since Fuzzy Zoeller in 1979.
"There's been a lot of close calls from the last time I won until now. It would be a lie if I didn't say that it was eating at me a little bit," Spieth said.
"It's tough when you get so close so many times in big events against world-class fields and you're not able to pull it off.
"I decided to take care of business today. It was just one of those rounds where I was in the zone and just focusing on each shot.
"At no point was I upset, it was very stress-free."
Spieth took a grip on the final round with three consecutive birdies from the fifth to the seventh holes to go nine under and led by three strokes at the turn.
He had few problems holding on to his advantage in the homeward nine with four more birdies in his closing five holes.
With his commanding victory, Spieth's world ranking is expected to climb from 14 to 11.
"I certainly have not played better than today. I felt it coming on last week (in Japan), striking the ball very well and my putter was close," he said.
"I came into here with a lot of confidence and I had my coach here and so I knew that having him to cope with the little things that this could be a really good week."
Spieth finished the 72 holes of the tournament with 22 birdies and just nine bogeys.
Australian Rod Pampling finished second at seven-under 277 with Brett Rumford third on six-under 278 and Greg Chalmers in fourth on five-under 279.
Scott lost momentum with a double-bogey seven at the fifth hole to drop back to two under and could make little headway on the tearaway leader to finish fifth with four-under 280.
The world number three had to take a penalty drop for an unplayable lie after blocking his tee shot into rough and then hooked his next shot back into the trees on the left.
He speared through a narrow opening but was unable to get up and down, the double-bogey leaving Scott five behind Spieth at that stage.
Defending champion McIlroy, who beat Scott with a birdie at the final hole at Royal Sydney last year, wrestled with the course and the windy conditions and finished joint 15th at two-over 286, 15 strokes behind Spieth.
It was a torrid week for McIlroy, who carded 15 birdies, an eagle, 14 bogeys, one double bogey and a disastrous triple bogey.
Only eight players finished under par over the 72 holes at the demanding Jack-Nicklaus designed course.
Spieth joins past winners of the Stonehaven Cup such as greats Jack Nicklaus, Gary Player, Greg Norman, Tom Watson and Peter Thomson.
He is the first American to win the Australian Open since Brad Faxon in 1993.
Spieth won the John Deere Classic aged 19, becoming the first teenaged winner of a US PGA Tour event since 1931.
The Australian trio of Rumford, Pampling and two-time winner Chalmers qualified for next year's British Open at St Andrews as the top three non-exempt players.Leading scores after the final round of the Australian Open at The
Australian course (par-71) in Sydney on Sunday (Australia unless
271 - Jordan Spieth (USA) 67-72-69-63
277 - Rod Pampling 73-67-69-68
278 - Brett Rumford 70-69-69-70
279 - Greg Chalmers 71-66-71-71
280 - Adam Scott 74-66-69-71
281 - Jake Higginbottom 71-69-72-69
283 - Robert Allenby 71-69-73-70, Ryan Fox (NZL) 72-72-69-70
284 - Daniel Nisbet 74-72-67-71
- Nathan Holman 73-72-73-67, Sung-Hoon Kang (KOR) 73-70-72-70, Aaron
Townsend 73-70-71-71, Josh Younger 71-72-70-72, Aron Price 68-75-69-73
- Stephen Dartnall 72-71-74-69, Stephen Allan 75-71-70-70, Steven
Bowditch 70-74-71-71, Rory McIlroy (NIR) 69-69-76-72, Richard Green
69-71-74-72, Boo Weekley (USA) 72-71-71-72, Alistair Presnell
74-72-68-72, David Bransdon 72-70-71-73
287 - Conrad Shindler (USA) 70-68-81-68
289 - Patrick Rodgers (USA) 70-74-77-68, Jin-ho Choi (KOR) 74-68-75-72
290 - Joon-woo Choi (KOR) 72-71-73-74
291 - Brendon De Jonge (ZIM) 69-75-73-74
293 - Garrett Sapp (USA) 73-72-72-76
294 - Jin Jeong (KOR) 71-75-77-71, Kyle Stanley (USA) 74-72-76-72
296 - Jamie Lovemark (USA) 77-65-79-75