GOLF: McIlroy's Masters cruise hits the skids at Amen Corner

Rory McIlroy arrived at Augusta National on Saturday with one arm already slipped into the Green Jacket but the defending champion left the course with a fight on his hands.

The Northern Irishman had built the biggest 36-hole lead in Masters history and looked to be barrelling toward a stress-free Sunday stroll around Augusta National.

But it took just 12 holes on Saturday for his six-shot cushion to evaporate, undone by a brutal trip through Amen Corner — the picturesque but treacherous three-hole stretch that often proves pivotal at the Masters.

"This golf course has a way of, you know, when you're not quite feeling it, you struggle," said McIlroy.

Standing in the 11th fairway with a three-shot lead, McIlroy's approach shot bounced off the front of the green and rolled into the water, leading to a double-bogey.

He then bogeyed the par-three 12th after sending his tee shot behind the green.

The five-times major champion, who had covered those same three holes in a combined three-under over the first two rounds, steadied the ship with birdies at 14 and 15 to regain the lead, but a poor tee shot at 17 led to another bogey, leaving him bent over in disbelief.

"I have to look at the positives even though there isn't that many to take today," said McIlroy. "But I did bounce back. I hit some good shots coming in."

He will need more of those on Sunday as he looks to become just the fourth repeat Masters champion -- and first since Tiger Woods in 2001-2002 -- with Cameron Young, who started the day eight back, now level and breathing down his neck.

"There was a lot of guys that shot good scores," said McIlroy. "I'm still tied for the best score going into tomorrow, so I can't forget that, but I do know I'm going to have to be better if I want to have a chance to win."

McIlroy infamously collapsed from a four-shot lead heading into the final round of the 2011 Masters, a meltdown that led to years of questions about whether he'd ever win a Masters.

He finally answered the call last year by winning a sudden-death playoff to complete the career Grand Slam of golf's four majors and he expects that having that garment in his closet will help him in the final round.

"I'd like to think that I'll play a little bit freer and I'll play, you know, like I've already got a Green Jacket, which I do," said McIlroy. "Sometimes I may just have to remind myself of that."

-Reporting by Frank Pingue in Augusta, Georgia; Editing by Peter Rutherford/Reuters