The cheers at the British Open are invariably and eternally appropriate, not to mention ridiculously precise. An approach struck to 25 feet from the pin is treated as such, with appreciation. One that settles at five feet is — every single time — acknowledged more loudly, and for longer. The applause is directly commensurate with the accomplishment.

So the gallery that filled the grandstands that surround the 18th green at Royal Liverpool Golf Club knew exactly what was unfolding in front of them Saturday afternoon, and responded in kind. Rory McIlroy tried everything he could — raising his putter, tipping his cap, waving his hand — as he walked to the green, where the last of his majestic shots had just landed. Ninety minutes earlier, he had been tied for the lead at the British Open. But here he was, ready to open a six-shot advantage .

“I got goose bumps,” McIlroy said.

Then, when he rolled in his 10-footer for his second eagle in the final three holes, he gave the goose bumps right back. McIlroy stands at 16 under par, and barring some combination of collapse and comeback, he is in position to capture the third leg of the career Grand Slam on Sunday evening. He is 25.

“I would be in some pretty illustrious company,” McIlroy said. “Not getting ahead of ourselves here . . .

He is in this position, though, precisely because he didn’t get ahead of himself on an unusual British Open Saturday, one in which the leaders teed off at 11 a.m. and the field played from both the first and 10th tees because of predicted thunderstorms. McIlroy began the day with a four-shot advantage on Dustin Johnson, six on a pack of others. When he walked off the 12th green, the lead was gone. Rickie Fowler — the field’s other 25-year-old star, playing a group ahead of McIlroy — had to that point made seven birdies.

“I was playing very solidly,” Fowler said.

Here’s where McIlroy could have bobbled. For all his accomplishments so early in his career, he is not without scars. In 2011, he led the Masters after each of the first three rounds before crumbling, a final-round 80 . His narrative always will include his rebound from that performance, because two months later, in the U.S. Open at Congressional, he led again after 18, 36 and 54 holes — and slammed the door for his first major title.

So with Fowler playing superbly and McIlroy seemingly uncertain, the latter drew on all his experiences.

“I never panicked,” McIlroy said. “I didn’t feel uncomfortable.”

Royal Liverpool provided part of the reason why. Reconfigured for the Open so that what the members play as the 16th hole serves as the last, it provides two par 5s down the stretch. They are, for a player who is driving the ball as well as McIlroy, opportunities. And as he moved forward, regardless of the status of the match, they sat ahead, waiting to welcome him.

“I knew that I had some holes coming up that I could take advantage of,” McIlroy said, “and make some birdies on the way in.”

Or better. He got a bonus at 14 when a 40-footer for birdie dropped, and the part that was out of his control — his competition — complied as well. Fowler made bogeys at Nos. 14, 16 — inexcusably — and 17 to let what could have been a stellar round slip away, finishing with 68 to get to 10 under. Johnson, playing with McIlroy, at one point was 2 over for the day before making three birdies coming in, but that gave him 71 and got him only to 9 under. Sergio Garcia, playing with Fowler, made birdie at 16 but gave it back immediately with a bogey, and his 69 also left him at 9 under .

So here came McIlroy to the 16th tee, driver in his hands. The hole plays 577 yards, and McIlroy absolutely uncorked one. He was left with 252 yards to the hole, and pulled 4-iron. It settled 20 feet from the flag, and when the putt dropped in, the crowd responded exactly as it should have: bedlam.

“I heard the roar when I was on 18,” said Jim Furyk, playing three groups ahead. “I assume he eagled 16.”

His lead was back to five, and though he gave one back at 17, the final hole beckoned. Again, a driver. Again, a majestic strike. This time, on a 551-yard hole, he had 239 to the pin. He covered it with a 5-iron to those final 10 feet, and the adulation — befitting what was unfolding, as it does every time here — came down from the crowd.

“I felt like those two shots into 18 deserved an eagle,” McIlroy said. “I wanted to finish it off that way.”

So this is what Fowler and the rest will face on Sunday, having to overcome the lead, the crowds and McIlroy’s currently impeccable game. When Tiger Woods won the Open here in 2006, he stood at 13 under after three rounds, holding just a one-shot advantage before closing with 67. Fowler is no stranger either to McIlroy — the two are near-neighbors in the West Palm Beach, Fla., area — nor to his position, because he played in the final group of the U.S. Open with Martin Kaymer, who led by five headed into Sunday.

“If I’m able to go out and get off to a good start, maybe I can put a little bit of pressure on him,” Fowler said, “because he’s definitely in control of the golf tournament right now.”

He is in control of everything, including the reactions of the crowds. And if McIlroy makes that walk up 18 one more time holding a lead, listen, then feel. The goose bumps will be warranted.