So rare was McIlroy's feat of going back-to-back that Augusta National that club chairman Fred Ridley was forced to hand over the prized spoils after the talismanic Northern Irishman secured a rousing one-shot victory on Sunday.
Masters tradition has the defending champion put on his successor's jacket but that was McIlroy himself after surviving some inevitable twists and turns to grind out a closing one-under par 71 and deny world No.1 Scottie Scheffler an improbable third Masters win.
"We did it again," McIlroy said to his father as he embraced his family by the 18th green.
Despite being the first player since 1942 to go bogey-free over the weekend, Scheffler had to settle for solo second after a final-round 68 - having been a distant 12 shots behind leader McIlroy after Friday.
Three-time runner-up and many fans' sentimental favourite Justin Rose (70) can add an equal-third to his CV after relinquishing a back-nine lead to finish two strokes behind McIlroy's 12-under 276 winning total.
After starting with a share of the 54-hole lead with Cameron Young, and briefly falling two shots behind Rose, McIlroy steadied to become the first player to successfully defend the title since Nick Faldo in 1990.
Having finally completed the elusive career grand slam with an epic play-off victory last year over Rose, McIlroy also joins legends Jack Nicklaus (1965-66), Tiger Woods (2001-02) and Faldo as only the fourth player to go back to back.
"I just can't believe I waited 17 years to get one green jacket, and I get two in a row," the Holywood-born hero said after scripting his perfect Hollywood sequel.
"All of my perseverance at this golf tournament over the years has really started to pay off. It was a tough weekend. I did the bulk of my work on Thursday and Friday.Â
"But just so, so happy to hang in there and get the job done."
In capturing a sixth major championship, the 36-year-old climbs above Australian Peter Thomson, Seve Ballesteros and modern-day rival Brooks Koepka among the pantheon of greats.
McIlroy joins Faldo, Phil Mickelson and Lee Trevino on the all-time list, with the seven majors secured by Bobby Jones, Gene Sarazen, Sam Snead and Arnold Palmer next in his sights.
But, after breaking the shackles, he now craves many more.
"I think different," McIlroy said.
"At the start of the weekend here, I felt like the grand slam was the destination, and I realised it wasn't. I'm on this journey to ... I don't know.
"I just won my sixth major and I feel like I'm in a really good spot with my game and my body.
"I don't want to put a number on it. I still have things I want to achieve.
"It took me 10 years to win my fifth major and then my sixth one's come pretty soon after it - but I certainly don't want to stop here."
But McIlroy's latest success was anything but a Sunday walk in the park.
After surrendering his six-shot halfway lead with a faltering third-round 73, McIlroy found himself two behind Rose after making a three-putt double bogey on the fourth hole.
But not even the looming shadow of a charging Scheffler could spook McIlroy as he resisted the world No.1's surge with some stellar golf of his own down the stretch.
With a disappointing, birdie-less three-over 75, Day slumped from tied fifth to joint 12th at five under - seven shots behind McIlroy.
Tellingly, though, the top-12 finish earned Day an invite back next year for what would be the one-time runner-up's 16th Masters tilt.
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