LOUISVILLE — Rory McIlroy has the boyish smile and the endearing manners of a proper Irish schoolboy, but don't let that fool you. He's calculating and cold-blooded on the golf course.
As darkness fell on Valhalla on Sunday evening, McIlroy won the 96th PGA Championship with a gutsy comeback that earned him his second major title in a month.
Only 25, he's the third youngest player, behind Jack Nicklaus and Tiger Woods, to win four majors.
In his three previous major victories, McIlroy enjoyed comfortable leads on Sunday. This time around he had to scratch and claw his way back from three shots down.
"It is more satisfying to win in this fashion and style," he said. "It means a lot to know I can come from behind and mix it up with the best players in the world and come out on top."
He did it by playing the last 12 holes 5-under par, including a stunning eagle at the 10th hole. McIlroy's second shot on the par 5 was a stroke of genius — a 284-yard 3-wood — that ended up seven feet from the cup.
He called it a "lucky shot" because "the ball flight was probably 30 feet lower than I intended."
No way he was going to miss the putt. He sank it to get to 14-under, pulling him to within one shot of Fowler.
"That sort of kick-started everything," McIlroy said.
It was a memorable duel down the stretch as McIlroy battled Phil Mickelson, Rickie Fowler and Henrik Stenson.
McIlroy and Mickelson were tied at 15-under until Mickelson dropped a shot at the 16th when he failed to get up and down from in front of the green. That ended his string of 21 holes without a bogey.
"I botched it," Mickelson said of his chip shot. "I flew it way too far."
McIlroy, who won the British Open last month by making big shots when he absolutely had to have them, did it again. He birdied the 17th out of a fairway bunker to get to 16-under.
That gave him a two-shot lead with the par-5 18th left.
It was a strange sight on the last hole. With the last glimmer of light fading, Mickelson and Fowler teed off.
After they made their way down the hill and before they reached their tee shots, they got out of the way and let McIlroy and Bernd Wiesberger hit their drives.
McIlroy said he later thanked Fowler and Mickelson for showing "a lot of class and sportsmanship. If they hadn't done that, we probably wouldn't have been able to get it done because it was getting really dark out there."
After leaving his second shot just off the right side of the green, Mickelson's 30-yard chip almost went in for an eagle. He settled for a tap-in birdie, putting him at 15-under.
That meant McIlroy needed only a par. His second shot found the deep bunker in front of the green. He got out safely, got his two-putt par, then screamed for joy.
Mickelson, who didn't have a top-10 finish this year before Sunday, said he enjoyed being back in contention in a major.
He and Fowler had a good time, and they set a record for fist-bumps exchanged by playing partners in a major.
"Between Rickie and I, we kept going back and forth birdieing holes. Our best-ball score was pretty darned good, and we had a lot of fun."
This was Fowler's fourth close call in a major this year. He tied for fifth in the Masters, tied for second in the U.S. Open and British Open, and tied for third this week.
"This is probably the one that hurts the most for me," Fowler said. "The first three were a lot of fun ... This one I felt like I could go out and win it. I put myself in a good position."
Fowler had the lead to himself briefly on the front nine, "but the back nine wasn't what I was wanting.
"Still, to look back on the year, it was pretty awesome through the majors and something I can look back on and be proud of."
Stenson, trying to become the first Swede to win a major, birdied the 13th to tie for the lead at 15-under. But a bogey at the 14th did him in.
Having won four majors since 2011, McIlroy said his next two goals are completing the career Grand Slam and becoming the most successful European player ever.
He'll try for the career Grand Slam when he plays the Masters next April. Nick Faldo set the standard for Europeans with six majors.
But McIlroy admits to being surprised by all that he's already accomplished.
"I thought winning the (British Open) a few weeks ago sort of put me on a higher level in this game," he said.
"To win a fourth major here, to be one behind (Mickelson), one behind Seve (Ballesteros), level with Ernie (Els), level with Raymond Floyd. I mean I never thought I'd get this far at 25 years of age."