Before long, an older woman living nearby came out to protest - McIlroy and his buddies were making too much noise. They obediently stopped the frivolity and went back inside. Who says kids today don't respect their elders?
McIlroy needed his rest, anyway, on the eve of Thursday's opening round at Augusta National. He took advantage of ideal scoring conditions - warm and sunny, little wind, friendly pin positions - to breeze around the storied layout in 7-under-par 65, seizing a share of the lead.
Alvaro Quiros, a long-hitting Spaniard, later matched McIlroy. Y.E. Yang and K.J. Choi shot 67 to trail by two, with Ricky Barnes and Matt Kuchar another stroke back at 68. Phil Mickelson posted 70 and Tiger Woods shot 71.
But in a golf world clamoring to know which young players will lord over the game the next two decades, in a Tiger/Phil kind of way, McIlroy offered another clue he's the leading candidate. He's only 21, a fresh-faced lad from Northern Ireland with a tantalizing combination of power and poise.
He's won a PGA Tour event (2010 Quail Hollow Championship), unlike Rickie Fowler. He knows when he's in a bunker, unlike Dustin Johnson. And he brings a burgeoning track record in majors (three ties for third in the past two years), unlike just about every other promising boy wonder.
Martin Kaymer might reside at No. 1 in the world rankings, and own a major title (last year's PGA Championship), but it requires little imagination to picture McIlroy as more of a long-term force, especially at Augusta National.
"Rory's very close," Australian Jason Day said after playing alongside McIlroy. "He's there right now. You can see how confident he is out on the course, and Rickie is right behind him."
Day (age 23), Fowler (22) and McIlroy form the new-wave group for the first two days of this Masters. Fowler wore an all-green outfit Thursday, a shade lighter than Augusta National's famous jacket. He and McIlroy talked about cars and boats - fast, expensive cars and boats, no doubt - as they marched along the fairways.
The galleries noticed as McIlroy, Fowler (70) and Day (72) unleashed a barrage of back-nine birdies. The crowds at golf tournaments, and especially the Masters, tend to skew older, but this dynamic trio attracted a noticeably younger audience.
"There was definitely a lot of energy going around with our group," Fowler said. "It's always nice to see young fans out there, to know we have some impact on who's showing up. ... We have to be the next generation - we're young, and the other guys are getting older."
The landscape clearly has changed since McIlroy made his Masters debut two years ago. Back then, Woods still wore a coat of armor and Mickelson still was in his 30s. McIlroy was the bold and reckless teenager, surging onto the second-round leaderboard and falling back just as quickly.
Even last year, he followed splashy rounds with sloppy ones. Witness his opening-round 63 in the British Open at St. Andrews ... and his buzz-killing 80 the next day.
McIlroy insisted he learned from the experience, much as he learned from his previous two appearances at Augusta National (tie for 20th in 2009, missed cut last year). That was evident Thursday, when he routinely put his ball in the right spots and didn't really come close to making a bogey.
Fowler and Day were impressed. They're both Masters rookies, taking their maiden voyage around Augusta National - trying to learn how to attack, how to read the tricky greens, how to zoom to the top of the leaderboard, as McIlroy did, becoming the youngest leader in Masters history.
Day found amusement in his status as the oldest player in the threesome, evident in the way he lagged behind McIlroy and Fowler all day.
"I am the old man in the group," Day said. "Those two blokes walk as quickly as possible. I couldn't keep up with them."
He might not be the only on saying that in the years ahead.
Leaders
Rory McIlroy 65
Alvaro Quiros 65
Y.E. Yang 67
K.J. Choi 67
Matt Kuchar 68
Ricky Barnes 68
Notables
Sergio Garcia 69
Retief Goosen 70
Phil Mickelson 70
Tiger Woods 71
Lee Westwood 72
Dustin Johnson 74
