Jack Nicklaus was lining up his birdie putt on the ninth green at Augusta National when he heard a roar that startled him, and then another one moments later just as loud. Tom Kite and Seve Ballesteros had each made an eagle behind him in the 1986 Masters.

Turning to the gallery, Nicklaus said, "Why don't we see if we can make a little noise up here ourselves?"

He poured in the putt, headed to the back nine and delivered one of the most famous charges in tournament history for his sixth green jacket.

The Masters really doesn't start until the back nine Sunday.

Everyone knows that.

It begins with a 95-yard walk through a narrow corridor of spectators, past the 18th green on the right and the three-story clubhouse on the left, straight ahead to the 10th tee and what amounts to the starting line.

Most years, the previous 63 holes are just the opening act.

For Nicklaus and Nick Faldo, for Phil Mickelson and Adam Scott, the back nine is where they won the Masters. For Greg Norman and Ed Sneed, for Tom Weiskopf and Rory McIlroy, that's where the Masters got away from them.

There is a long list of charges and collapses, all of them adding to the lore of what might be the greatest theater in golf.

"It's a great feeling to know you have a chance," said Brandt Snedeker, who has been there twice without winning. "It's also a complete feeling of uncertainty, realizing you've worked your tail off for 63 holes and you're starting over again."

Adam Scott knows the feeling. He was three shots behind in 2013 when he headed to the 10th tee and made three birdies to catch Angel Cabrera and win in a playoff.

"The energy walking up the chute to No. 10 is some of the most you'll feel," Scott said. "If you're in the hunt, you know what you're walking into. And they'll remind you if you try to block it out. But that's the beauty of the place. It's really maybe the greatest stadium there is in golf."

It can be said that no golf tournament starts until the back nine on Sunday, whether it's the TPC John Deere or even the Old Course at St. Andrews. But there is nothing like Augusta National, a back nine that descends into a valley and becomes an echo chamber of cheers for the final two hours.

The noise cannot be ignored. It energizes. It haunts. Most of the time, players aren't entirely sure who it's for or what it means.

"If you're leading on the back nine of the U.S. Open, you know if you par in you're going to win," said Geoff Ogilvy, who made five straight birdies on the back nine in the 2011 Masters until he ran out of holes.

"It's totally different at Augusta," he said. "You can have a four- or five-shot lead and par in and feel like you can lose."

The U.S. Open is all about surviving par. The British Open depends entirely on the weather, and the nature of the links. The PGA Championship depends on the course.

The Masters, with few exceptions, always seems to deliver.

The course can be set up for birdies, as was the case in 2004 when Mickelson and Ernie Els traded birdies for two hours until Mickelson, who birdied five of his last seven holes for a 31 on the back, curled in one last putt for birdie on the 18th and his first major.

Jason Day has had a couple of chances to win majors — at the Masters in 2011 and 2013, and at the U.S. Open at Merion in 2013. There's a difference. The U.S. Open was a grind, and the Australian had to plot his way around to figure out where he could pick up a rare birdie and how to hold on with the pars.

What's it take at the Masters?

"If I hit a good one down 10, I can make birdie," he said. "On 11, I'll take par. Twelve, I can birdie. Thirteen, I can birdie or eagle. Fourteen, 15, 16, I can birdie, and 17, you can be on the verge of birdie. And 18 you can birdie."

A birdie on just about every hole?

Nicklaus shot 30 on the back nine when he won in 1986, including a bogey on the par-3 12th. Mickelson birdied five of his last seven. And then there was Charl Schwartzel, who turned a fantasy finish into reality with birdies on the last four holes to win in 2011, the Masters that featured eight players with a share of the lead at some point in the final round.

Snedeker played his first Masters in 2004 as the U.S. Public Links Amateur champion. He made the cut, though he was finished early. Instead of leaving, he hung around the locker room to soak up the atmosphere and got his first taste of the back nine at Augusta. And he was indoors.

"I could hear the roars before they came on TV," he said.

Four years later, he was in the middle of it trying to catch up to Trevor Immelman and charging in the wrong direction.

"There's just so much that can happen on that back nine," Snedeker said. "It's tough to stay in the present. You can hear it, you can see it, more than any place we play all year. That's probably why there's a lot of movement on the back nine, because you start playing differently when you hear something in front of you."

That's how Augusta National likes it, and it might not be an accident. The greens have so much slope that holes can be placed in positions where the ball funnels toward it and sets up easy birdies. The worst years at the Masters are the quietest years when there is little reason to cheer. Those are rare.

"It's about setting up the course exactly how they know it works best," Ogilvy said. "And they've got it down to a science. They set up the first 63 holes purely to get the tournament going on the 10th tee. That's what it feels like, anyway."