In the heady moments after the greatest victory of his burgeoning career, just before he took possession of his latest trophy, Rory McIlroy had a couple of minutes to kibitz with his small, fiercely loyal tribe: father Gerry, who walks every hole with his son, suffering palpably; swing coach Michael Bannon, so modest and unassuming he rarely grants interviews; manager Sean O'Flaherty, a devoted lieutenant who has helped McIlroy navigate some very choppy waters; and best friend Harry Diamond, whom McIlroy often imports to tournaments to replicate a sense of normality. When someone suggested Gerry should join his son on Valhalla's 18th green for the trophy ceremony, Rory snorted, "No way—his head is getting big enough already!" McIlroy made mention of his decisive birdie on the 71st hole: "Not bad from statistically the worst fairway bunker player on the PGA Tour." Everyone began working their phones madly, and as the jocularity ebbed, McIlroy suddenly had his head in his hands and was crouched down, as if feeling the weight of history for the first time. Looking back on that moment a bit later, he said, "I was trying to gather my thoughts a little bit and just think back about what has happened this summer and what a great run of golf it's been. I was just trying to let it all sink in."

What has happened is that McIlroy has reinvented the game in his image while taking his dominance to a Tigeresque level just as Woods's decline has accelerated. At last month's British Open, on a breezy, quirky course hard by the Irish Sea, McIlroy put on a show of pyrotechnics that has already passed into legend, securing the third leg of the career Grand Slam and quieting skeptics who said his game is ill-suited to links golf. Last week, at the 96th PGA Championship, McIlroy summoned the grittiest performance of his career, proving he could survive a dogfight on the most pressure-packed of Sundays. "It's the most satisfying one," he said.

McIlroy never had his best stuff across the first three rounds at soggy Valhalla Golf Club, in Louisville, but he scrapped his way to a one-stroke lead. He came out flat on Sunday, and standing in the 10th fairway, he was three off Rickie Fowler's lead and also staring up at the big-time duo of Phil Mickelson and Henrik Stenson. McIlroy proceeded to eagle the par-5 and blow everyone off the course with a flawless back-nine 32. "It was all heart," said caddie JP Fitzgerald.

With his four career major championships, McIlroy, 25, has matched the haul of Hall of Famers Ernie Els and Ray Floyd. Next on the list with five are, among others, Mickelson, Byron Nelson and Seve Ballesteros, the only European with a gift and swagger comparable to McIlroy's. Last week Jack Nicklaus opined that McIlroy could win 15 or 20 majors, but Graeme McDowell believes it's folly to put a limit on his friend's future. "He'll win as many majors as he wants," he says.

McIlroy's run began in May after his breakup with tennis starlet Caroline Wozniacki just days after their wedding invitations had been mailed. He immersed himself in training—"I've got nothing else to do"— adding five pounds of muscle and honing his short-iron play. This marriage of power and finesse was never more evident than at the 508-yard 16th hole on Saturday, as McIlroy smoothed a 9-iron to within inches for a kick-in birdie. "Christ, I can't reach with a driver and three-wood," said Colin Montgomerie. "He's playing a completely different course not just from me but a lot of others too."

McIlroy next has a date with destiny at the 2015 Masters, where he will attempt to become the sixth player to complete the career Grand Slam. ("Only 242 days away," McIlroy noted on Sunday, with characteristic cheek.) His high draw sets up beautifully for Augusta National, but he's been star-crossed there ever since blowing a four-stroke Sunday lead in 2011. That painful day began his evolution into a cutthroat closer. "Look, I went protection mode once in my career, and it was the 2011 Masters," McIlroy said last week. "That didn't work out very well. So I said to myself, I'll never do that again. You know, my mind-set has stayed the same since that day at Augusta. If I'm two ahead, I'm going to try to get three ahead, and if I'm three ahead, I'm going to try to get four ahead. I'm just going to try to keep the pedal down and get as many ahead as possible."

This is not so much a course strategy as a worldview. As McIlroy proved last week, there's no stopping him now.

PHOTOPHOTOGRAPH BY FRED VUICH FOR SPORTS ILLUSTRATEDLONG RANGE McIlroy overpowered Valhalla, averaging 298.4 yards off the tee, best in the field. PHOTOPHOTOGRAPH BY FRED VUICH FOR SPORTS ILLUSTRATEDLEFT SHORT Mickelson tried to summon some 72nd-hole magic, but he came up a shot shy. PHOTOPHOTOGRAPH BY FRED VUICH FOR SPORTS ILLUSTRATEDSPOTLIGHT McIlroy, who shared a hug with Gerry (above right), became the fifth player to win multiple majors in a season before age 26.