LOUISVILLE, Ky. — The challenge finally arrived for Rory McIlroy, and he was better than ever Sunday to win the PGA Championship.
On a back nine filled with clutch shots and as much tension as a major can provide, McIlroy emerged from a four-man race to outlast Phil Mickelson and the darkness at Valhalla to capture his second straight major and his second PGA Championship.
McIlroy closed with 3-under 68 to total 16-under 268 and become the fourth-youngest player to win four majors.
"I didn't think in my wildest dreams I'd have a summer like this," said McIlroy, the seventh player to win the last two majors of the year and the first since Padraig Harrington in 2008. "I played the best golf of my life. I really gutted it out today."
But one of the greatest shows golf has seen in a while came with a peculiar ending.
Three shots behind going to the back nine, McIlroy rallied to take the lead and then hit a 9-iron from the fairway bunker to 10 feet for birdie on the 17th hole for a two-shot lead going to the par-5 18th. Because of a two-hour rain delay earlier, darkness was falling quickly, and it wasn't certain McIlroy, in the final pairing as the third-round leader, would be able to finish.
McIlroy was allowed to hit his tee shot before Mickelson and Rickie Fowler, who were only two shots behind, had reached their drives. McIlroy came within a yard of hitting in a hazard right of the fairway.
Then, the PGA of America allowed McIlroy to hit his second shot. Mickelson and Fowler had to stand to the side of the green.
"We were cool with hitting the tee shot," Fowler said. "We weren't expecting the approach shots."
Fowler had a 50-foot eagle attempt to tie for the lead. He was well off the mark and missed a short birdie putt that cost him his third straight runnerup finish in a major. Mickelson was short of the green, and his chip came within inches of dropping for an eagle that would have tied him for the lead.
Mickelson appeared upset that they had to wait to finish the hole — not standard procedure in a PGA Tour event — and he made two references in a TV interview that this is the only championship the PGA of America runs all year.
"It didn't affect the outcome of the championship at all, I don't think," Mickelson said. "It's not what we normally do. It's not a big deal either way."
He shot 66 and was a major runnerup for the ninth time.
Fowler closed with 68 and tied for third with Henrik Stenson (66), who fell out of a share of the lead by missing a 3-foot par putt on the 14th hole.
Fowler became the first player to finish in the top five at all four majors in one year without winning one. He is just the third overall to finish in each major's top five. The other two are Jack Nicklaus and Tiger Woods, who each have done it twice.
He didn't need any time to name the emotion he felt sharply: "Right now, the sting. I really felt like I could win this one."
McIlroy hit his second shot at No. 18 into a bunker, and he had to two-putt from 35 feet for the win. He lagged the first one to tap-in range, and the major was his. McIlroy repeatedly pumped his right fist before letting out a scream above the gallery that had been treated to one of the best shows in a major.
He won his first two majors by eight shots, at the 2011 U.S. Open and 2012 PGA Championship. Last month, McIlroy took a six-shot lead into the final round of the British Open and completed a wire-to-wire win with only a brief scare. This was his first big test. "I think I showed a lot of guts out there to get the job done," he said.
The winning shot turned out to be that 9-iron from the bunker and the birdie putt on the 17th hole that gave him a two-shot lead, the largest margin for anyone on a day when as many as five players had a share of the lead.
Not since Tiger Woods in 2008 has anyone won three straight tournaments, and they were big ones for McIlroy: the British Open, a World Golf Championship event at the Bridgestone Invitational and the PGA Championship. He played them in a combined 48 under par.
"He's better than everyone else right now," Mickelson said.