"Valhalla might be the mythological palace where the Norse heroes killed in battle feast with Odin for eternity but for Rory McIlroy it's just another stop on the road to golfing immortality.
In a final round that will go down as one of the most thrilling in recent major championship history — a huge contrast to the lack of drama of those impressive solo successes by Bubba Watson, Martin Kaymer and McIlroy himself in the first three majors of the year — McIlroy came from three shots behind Rickie Fowler at the turn, coming home in 32 to shoot a three under 68 and win the US PGA Championship by one from Phil Mickelson (66) on 16 under par as darkness descended on Louisville.
"To win my second major this year and my fourth at the age of 25, I can't describe the feeling right now, it's been incredible," said McIlroy, who admitted that his low, cutting three wood that set up the championship changing eagle three at the 10th was a somewhat fortunate.
"The ball flight was probably around 30 feet lower than I intended. And the line of the shot was probably around 15 yards left of where I intended. It was lucky, it really was. You need a little bit of luck in major championships to win and that was my lucky break. I didn't hit a very good shot there but it worked out well and I made eagle from it.
"So, yeah, you know, things can go your way and it seems like whenever you're on a run of form like I am, things sort of fall your way, and it seemed to today."
It was a thoroughbred performance in Kentucky Derby territory by the 25-year old from County Down, who captured his fourth major, his second in a row, and his third straight tournament win by gutting it out and executing shot after shot down the stretch in a display of guts and steel that was a joy to behold for everyone bar his victims.
"Today wasn't easy," McIlroy said. "I didn't get off to the best of starts, and the guys came at me pretty quickly and we were talking on the front nine and I just couldn't really get anything going.
"So I needed to sort of stay patient and just sort of bide my time and wait for something to click, something to happen and that something happened on the 10th hole. To make eagle there was a big turning point in the tournament, and from there, I kicked on and played some great golf down the stretch."
He added: "This was definitely a different way to win a major. The other three were quite comfortable. But I really had to gut that out today and dig deep and hit some clutch shots.
"I mean, to answer [a reporter's] question yesterday, when he said, would today be the most satisfying if I was able to gut it out and win ugly; yeah, it is. It is the most satisfying.
"To win it in this fashion and this style, it means a lot. It means that I know that I can do it. I know that I can come from behind. I know that I can mix it up with the best players in the world down the stretch in a major and come out on top."
Forget Tiger. This was a Nicklaus-like performance from McIlroy, who started haltingly with a three-putt bogey at the third and another at the tough sixth to go from one ahead at the start of the day to two behind before claiming the Wanamaker Trophy for the second time in three years with a steely display that underlines his superiority as the game's No 1 force.
"I said I thought winning The Open Championship a few weeks ago had sort of put me on a higher level in this game. But then to win a fourth major here, to be one behind Phil, one behind Seve, level with Ernie, level with Raymond Floyd; I mean, I never thought I'd get this far at 25 years of age.
"It's something that I'm just going to have to come to terms with in a way and just yeah, I mean, I was happy being a two-time major championship coming into this year, and all of a sudden I'm a four-time Major champion and going for the career Grand Slam at Augusta in 292 days, 291 days or whatever it is; not that I'm counting. (Smiling).
"Yeah, it's just been an incredible run of golf, and I just couldn't be more proud of myself or happier with where my game's at."
Five players were tied for the lead early on the front nine with Henrik Stenson and Bernd Wiesberger joining McIlroy, Fowler and Mickelson in the fray.
But one by one they faded like the light on a day that began with a torrential downpour that almost forced the championship into a Monday finish — a scenario that was avoided when Fowler and Mickelson hit their tee shots at the 18th and allowed McIlroy and Bernd Wiesberger to tee off as they walked to their drives.
There were many keys to a win that makes McIlroy the fourth youngest player to win four majors after Young Tom Morris (1872 Open), Tiger Woods (2000 Open) and Jack Nicklaus (1965 Masters).
He had to chip and putt off a downslope to set up his first birdie of the day at the seventh just to remain two behind with Fowler and Stenson, who led on 12 under at that stage.
"I just needed to make one birdie, that's all I was saying, just make one birdie just to settle yourself. I felt like the birdie on 7 was big. I was trying to get back to even par for the day after nine holes, so birdie the ninth hole to give myself some sort of momentum going into the back nine and wasn't able to do that. But then the eagle at 10 just sort of kickstarted everything."
Fowler, who has finished finished tied fifth, tied second, tied second and tied third in the majors this year, grabbed the championship by the scruff of the neck when he followed a bogey at the second with birdies at the third, fourth, fifth, and seventh to move to 14 under par.
The back nine was something of a disappointment for the young American, who came home in level par for a 68 that was worth a share of third with Stenson, who scorched to the turn in 30 but also came home in 36 for a 66 that left them on 14 under.
Mickelson was left to rue a hugely costly bogey at the 16th as he ended up with his ninth runner up finish in a major by following a magical outward half of 31 with a closing 35.
No-one played better on the back nine than McIlroy and the key to the entire tournament was undoubtedly the cut three-wood from 282 yards at the par-five 10th that picthed short of the green, ran up the left channel and onto the green, running up to just seven feet left of the cup.
No-one in the field had been able to hit that green in two all day but McIlroy not only produced that key shot at the key moment, he followed it by holing the putt to go from one over for the round to one under and to within one of the lead on 14 under par.
Swede Stenson, who has had four Top-Four finishes in his last six majors, birdied the 13th to join Fowler in the lead on 15 under.
But McIlroy was only getting into his stride and as his rivals started to flag, he appeared to get more focussed and determined.
Had he had his putting boots on, he might have won even more comfortably but missed a nine foot chance at the 11th and an eight footer for birdie at the 12th to remain one behind.
When he hit a 91-yard approach to aroudn eight feet at the 13th and rolled in the putt, his low fist pump was aggressive enough to wind even Joe Frazier.
Tied for the lead with Mickelson now, you could sense that he knew he was now the strongest man with the strongest hand over the finishing stretch and he went on to prove it in stunning fashion.
Fowler had bogeyed the par-three 14th, flaring his tee shot well right of the green and finished with four pars, lipping out for birdie at the last when it was clear his race was run.
When Mickelson drove in the rough at the 16th and then lipped out with a pitch before missing a 10 footer for par, McIlroy was back in the lead.
He had outside chances to birdie the 14th, 15th and 16th but once Mickelson had bogeyed the 16th, he deal the touranment the coup de grace at the 17th.
Bunkered off the tee, he hit a 150 yard approach to 10 feet and rolled the right to left putt straight in the middle to go the last two ahead.
Mickelson just failed with an attempted eagle chip and birdied to leave McIlroy needing a par to win.
Having almost hit is tee shot in the hazard right — it ended up three feet from the red line, McIlroy's lay up ran into a trap but he blasted out to 35 feet below the hole.
With two putts for the title in fading light, he duly took them, tapping in from less than a foot before punching the air in celebration. He repeated fist pump a few moments later such was the enormity of his satisfaction.
The mistakes, false dawns, near missed and other mishaps that have punctuated a brilliant career appear to be a thing of the past right now.
Talk will now turn to a possible third major win — and a career Grand Slam — at the Masters. If that happens, we'll head to Chambers Bay talking about a Rory Slam.
"I think I've got to take it one small step at a time. I think the two next realistic goals are the career Grand Slam, and trying to become the most successful European player ever. So Nick Faldo, most successful European ever in the modern era Nick Faldo has six. Seve has five. Obviously the career Grand Slam coming up at Augusta in eight months time or whatever it is, they are the next goals.
And hopefully, when I achieve those, I can start to think about other things. But right now, that's what my focus is. My focus is trying to complete this year Grand Slam and then move forward and try and become the most successful European ever, and hopefully in time, if I can do that, then I can move on and set different goals."
Given what he's already achieved, a god-like feat does not appear to be beyond this cold-blooded — but still baby-faced — assassin.