Adam Scott is lamenting an ugly drive and rough out-of-bounds ruling that blew his Australian Open hopes up in smoke.

Scott couldn't hide his frustration after his home Open bid disintegrated right before his eyes on the final three holes.

After draining a 40-foot birdie putt on the sixth hole - his 15th hole of the day after starting on No.10 - to snatch the lead, Scott lined up his tee shot on the par-four dreaming of lifting the Stonehaven Cup for a second time.

After playing faultless golf through 15 holes and saluting the growing crowd with a fist pump, Scott evoked memories of his 2013 Masters triumph.

But what followed was eerily similar to his 2012 British Open implosion when he dropped four shots in the final four holes to virtually hand the Claret Jug to Ernie Els at Royal Lytham and St Annes.

This time an errant hook off the tee box brought everything back down to earth with a bump.

The former world No.1 whacked his ball way left where it cannoned through thick shrubbery and against the fencing surrounding the practice range.

He angled up to try to chip the ball back on to the fairway left-handed, but was informed by tournament organisers he would have to play his provisional, which wasn't much better.

"I first asked if it was in bounds and I was told it was in," Scott said.

"While I was trying to work out what I could do, the ruling was checked and it was out of bounds.

"I didn't know how I was going to get myself into a spot to make a bogey and it didn't really happen.

"I think if it was the last hole, I might have stormed off.

"But I had to calm myself to play those last two holes and it didn't go my way."

Scott made par on his last two holes to register a three-under 68, but the damage was done.

He finished three shots short of a playoff, which Chile's Joaquin Niemann eventually won to claim the Stonehaven Cup from Japan's Rikuya Hoshino.

Australia's only ever Masters winner will now be left to stew over the costly triple-bogey.

"Everyone who doesn't win has one swing or a miss (that they regret)," Scott said.

"When you don't win, it's easy to find tons of shots.

"It's a shame. It didn't feel like the worst swing I've made, but it certainly was a shocking result."

But there was at least one silver lining on a day of disappointment for the 43-year-old, with Scott's equal-fourth placing earning him a ticket to next July's British Open at Royal Troon.

The leading three players who had not already qualified were rewarded with spots at the prestigious Scottish major.