Finishing 13-under par with a final round of a 6-under 66, McIlroy set a record by winning by the most strokes ever in the PGA Championship, a major that celebrated its 94th anniversary this season.
David Lynn was the runner-up at 5-under, while Tiger Woods finished -2 and tied for 11th place.
While experiencing a terrible winless streak for most of the season since his win at the Honda Classic earlier this year, McIlroy missed many cuts in PGA events and wasn't in contention at any majors until Kiawah.
And something certainly clicked for him on the South Carolina coast.
He shot out to a quick second-place start after the first round, shooting a 5-under 67, but remaining one stroke back of Pettersson. The second round would show The Ocean Course's true colors, with 30-mph winds swirling around the course. McIlroy would shoot a 74 (+3), to fall back into the pack. On moving day, dark clouds halted play just as McIlroy and Adam Scott were making dazzling birdie runs. McIlroy would pick up on the 10th hole Sunday morning to complete his third round, and shot another 5-under 67.
On Sunday, McIlroy was nearly flawless. Northern Irishman David Feherty, the on-course commentator for the final pairing, frequently stated that this was McIlory's greatest round. It would be hard to argue otherwise, as McIlroy seemed to pull off everything he wanted to accomplish.
The 23-year-old from Holywood, Northern Ireland, would not bogey in his final round, and would birdie the last two of three holes to seal his second major victory.
McIlroy now sits on the esteemed podium of multiple major winners at the age of 23 and 3 months. Tiger Woods had accomplished the feat at the age of 23 years and 8 months.
McIlroy fever is spreading throughout the U.S. and abroad, as the talented young golfer has recaptured the No.1 ranking after his big win. He has also garnered a following from the next generation of golf fans, and could perhaps challenge the Woods's following.
Although that prospect of a legitimate rivalry may take a while, there doesn't seem to be much doubt who the best two golfers in the world are right now: Woods and McIlroy.
And Woods better start taking this kid seriously or it could be McIlroy who surpasses Jack Nicklaus's record of 19 majors.