Rory McIlroy claimed his first title of the year at the Australian Open by a single shot on Sunday after home favorite Adam Scott bogeyed the final hole to lose a tournament he had dominated since the opening day.

McIlroy, who swallowed up Scott's four-shot overnight lead in the first eight holes, nervelessly sank a 10-foot birdie putt at the 18th to finish 18 under for the tournament with a final round seven-under 66.

Scott, who was seeking a rare triple crown of Australian titles after winning the PGA and Masters titles last month, missed a string of chances over the back nine to extend his lead and had just the single-shot advantage going into the 72nd hole of the tournament.

Rory McIlroy holds the Stonehaven trophy aloft after winning the Australian Open at the Royal Sydney on Sunday. [Photo by William WES / Agence France-Presse]

After firing his approach shot over the back of the green, the world No 2 overcooked his chip and sent the ball racing back past the hole before coming up short with a 40-foot par putt to give McIlroy a chance he grasped with both hands.

"I felt a bit sorry that I was the one that ruined the triple crown for him but I'm very happy," said McIlroy, who was facing his first winless season since 2008.

"I've been building confidence for a few weeks now. When I went to Asia I started to play really well.

"I've worked hard, I've put the hours in and I've practised hard and finally it's turned around for me."

In what looked more like a matchplay contest, the pair played together over the final two rounds in front of packed galleries at the Royal Sydney Golf Course, but the Northern Irishman never led the US Masters champion until the final stroke of the tournament.

Scott, who had led from the first day of the tournament when he smashed the course record with a 10-under 62, finished with a 71 for second place at 17 under, six clear of compatriot John Senden (66) in third.

He started the day with a three-putt bogey on the first hole but reclaimed the shot when he smashed a superb second shot from the fairway with a wood to set up a birdie on No 2.

McIlroy missed a birdie putt on the third hole, but took a stroke out of Scott's lead at the fifth when a sublime approach shot set him up for a birdie.

Another long and accurate iron shot at the par-5 seventh gave him an eagle and when Scott missed a four-foot birdie putt, the lead was reduced to just one stroke.

McIlroy drew even when he sank a six-foot putt to pick up a shot at the eighth before Scott lipped out with his shorter birdie putt at the same hole.