Rory McIlroy claimed his second Major title in four weeks and a third win in succession in a thrilling, weather-affected climax to the US PGA Championship on Sunday.
McIlroy carded a closing 68 at Valhalla to finish 16 under par, one shot ahead of Phil Mickelson after a remarkable final day which finished in near-darkness, with the lights blazing from the clubhouse behind the 18th green.
Rickie Fowler and Henrik Stenson had been part of a three-way tie for the lead with Mickelson on the back nine but dropped shots on the closing stretch to finish two behind McIlroy on 14 under.
A torrential downpour which flooded the course and caused a delay of almost two hours meant it was a race against time to get play finished, so much so that Mickelson and Fowler stood aside on the 18th to allow the final group to tee off.
McIlroy's drive finished dangerously close to the water to the right of the fairway, but a closing par was enough for the 25 year old to become the first player since Padraig Harrington in 2008 to win back-to-back Majors, his victories in the Open Championship and US PGA also sandwiched by a first World Golf Championships win in the Bridgestone Invitational last week.
Lifting the Wanamaker Trophy for the second time also makes the Northern Irishman the third youngest player after Tiger Woods and Jack Nicklaus to win four Majors, just one less than the total won by the late Seve Ballesteros and two behind Sir Nick Faldo.
"It's been just incredible," McIlroy said. "I didn't think in my wildest dreams I would have a summer like this. I just played the best golf in my life.
"I gutted it out today, it was a little different to my previous Major wins. I think I showed a lot of guts to get the job done.
"I want to thank Phil and Rickie for letting us tee off, if they didn't it would have been a struggle to finish. It showed a lot of sportsmanship and class from those two guys."
Asked if he considered not finishing the hole, McIlroy added: "No, I wanted to win this thing and get out of here! It was very tough with the bunker shot and the depth perception so I decided to just chunk it out there, take my two putts and run."
It was the fourth time McIlroy had held the 54-hole lead in a Major, the first leading to heartache in the 2011 Masters Tournament when he was four ahead entering the final round at Augusta National only to collapse to a closing 80.
Two months later he bounced back in spectacular style to win the US Open by eight shots at Congressional before winning the 2012 US PGA by the same margin at Kiawah Island.
Last month he led from start to finish at Royal Liverpool, taking a six shot lead into the final round before going on to win by two from Sergio Garcia and Rickie Fowler.
This time he started the day with a one shot lead but dropped two shots in his first six holes and trailed Fowler by three as he reached the turn, the American having recovered from a bogey on the second with four birdies in his next five holes.
The par five tenth had cost McIlroy a double bogey seven on Thursday, but three days later he hit a fairway wood to seven feet and holed the eagle putt to get back into contention in stunning fashion.
Mickelson then birdied the 11th to join his playing partner Fowler in the lead, the pair exchanging fist-bumps as they walked to the 12th tee, and Stenson made it a three-way tie with a birdie on the 13th.
Stenson had offered a prayer of thanks to the golfing Gods when his approach had just carried the water, only to three-putt the next to drop out of the lead and, with no birdies over the closing stretch, saw his chances disappear.
McIlroy missed good birdie chances on the 11th and 12th, the latter after seeing Mickelson in the group ahead hole from 30 feet across the green for an unlikely par.
But the World Number One made no mistake from eight feet on the 13th to get back into a share of the lead with five holes remaining.
Fowler was the first to crack under the pressure after a wayward tee shot led to a bogey on the 14th, and when Mickelson bogeyed the 16th, McIlroy was back in the outright lead for the first time since the third hole.
As the light quickly faded, McIlroy delivered the killer blow with a birdie from nine feet on the 17th to enjoy a two shot lead playing the last.
Mickelson almost holed his pitch shot for an eagle on the 18th, the birdie forcing McIlroy to make par for the win.
Mickelson said: "It was fun to get back in the mix and feel the pressure. I just ran out of steam after 12 holes.
"I wasn't really firing on all cylinders but making some key putts and had a nice round going. After that birdie on 11 I thought if I could get one or two more I would be right there and it was a costly bogey on 16 in the end.
"I am disappointed in the outcome, if I could have finished the last five or six holes strong it could have flipped the way I feel about the whole year."
There was almost embarrassment for US PGA president Ted Bishop as he dropped the lid of the trophy in the process of presenting it.
McIlroy, perhaps inevitably, made a one-handed catch to save Bishop's blushes.