Now it's time to say good night, and we'll give the final word to Jack Nicklaus - the man whose 18-majors record many think McIlroy could go on and match.

"Fantastic," said the Golden Bear. "It was really a great tournament. It was great theatre. Great golf, actually. It was one of the best tournaments to watch - because of such good play - that I have seen in a long, long time.

"Phil Mickelson was unbelievable. Just pure guts and really great golf. And Rickie Fowler was simply terrific. He played well all the way down the stretch, until he couldn't see at 18. No one could.

"Then Rory, who got three shots down, showed so much poise, confidence and determination coming down the stretch.

"Rory got the right break at the 10th hole with a great shot. He was off and running from there."

John from Holywood: From another ropey wifi campsite in Southern France...well done wee man...don't let the party let up...looking forward to Augusta... ps Den I have run out of beer send some over to cabin 30

The party has well and truly started.

Andrew from Belfast: 'Little' Northern Ireland have now won 6 of the last 20 golfing majors! Not bad for a nation of 1.5 million! We're the real home of golf!!!

With his fourth major title and first back-to-back feat after his Hoylake antics, Rory McIlroy has joined an impressive list of past champions (since World War One) who have also completed back-to-back wins.

Walter Hagen, Bobby Jones (twice), Ben Hogan (three times), Sam Snead, Arnold Palmer, Lee Trevino, Jack Nicklaus (twice), Tom Watson, Nick Price, Tiger Woods (five times), Phil Mickelson, Padraig Harrington. It's pretty much a who's-who of golfing titans.

Italian pro Matteo Manassero tweets:, external I was glued to the TV. They mainly talk about his driving but the strength of mind he showed is incredible!! @McIlroyRory great champion

Jay Townsend
former European Tour golfer & BBC Radio 5 live pundit

He is on track [to emulating Tiger Woods and Jack Nicklaus] but if he's going to achieve it take them one at a time. Tiger's done winning majors.

Nine-time major winner Gary Player tweets:, external Lights out. Congratulations Rory McIlroy on your fourth major at the PGA Championship. Great back nine. True grit. Respect. My very best. GP

This trophy is a bit of a handful - the lid falls off but Rory catches it before it hits the deck, before McIlroy finally hoists the beast aloft after a couple of efforts. He praises the sportsmanship of Mickelson and Fowler, for allowing him to play up behind them in the fading light, and it's another classy speech.

It was mum who Rory celebrated with first after his victory at the Open, this time it's his old man again. How good can this kid be? Ten majors? Eleven? Twelve? All of a sudden, it looks like anything is possible. I can't help wondering where Tiger Woods is now. For the sake of a yet-to-be-made movie, I hope he's pumping drives on a windswept range, thunder raging all around him...

Jay Townsend
former European Tour golfer & BBC Radio 5 live pundit

They all had one hiccup on the back nine. McIlroy did not. This was a truly amazing stretch that you don't see very often in the game. This is big boy stuff right here.

Image source, Getty Images

We saw the US PGA Championship's Wanamaker Trophy sitting forlornly in the rain earlier, like an abandoned child. One of the heftiest trophies in world sport weighs 27 pounds, is 28 inches tall and 27 inches from handle to handle.

Purchased by Rodman Wanamaker in 1916, 10 years later Walter Hagen was asked where the trophy was. Hagen, who won the tournament for four straight years from 1924-27, said he hadn't brought it because he had no intention of giving it away. In 1928, when Hagen was ousted as champion, he admitted he'd lost the trophy.

Legend has it Hagen went partying in Chicago after his 1925 triumph and forgot the trophy when he hopped in a cab. It was found in 1930 in an unmarked case in the basement of L.A. Young & Company, the firm that manufactured the Walter Hagen line of golf clubs.

But the PGA had already made a duplicate of the Wanamaker Trophy, and once the original was recovered it was safely put away. It can be found at the PGA Historical Centre in Port St. Lucie, Florida.

Iain Carter
BBC golf correspondent at Valhalla

What an achievement, what a summer, what an amazing sustained performance we've seen from Rory McIlroy. He takes another giant leap in the dark on his way to golfing greatness. McIlroy is undoubtedly the superstar of golf right now. It's utterly unbelievable the way he's taken the golf world by storm.

Image source, Getty Images

... McIlroy pops in for par, a round of 68, victory over Phil Mickelson by a single shot and his fourth major title. What a championship...

McIlroy cosies his birdie putt up there to within a couple of feet of the hole - I've seen them missed, but only on municipal pitch and putts. Wiesberger finishes with a par, a disappointing round of 74 and nine under overall...

McIlroy rather muffs his sand escape but he's got another two putts for the title, albeit from 34 feet...

Fowler's birdie effort lips out, he has to make do with a tie for fourth with Stenson. But that's four top-five major finishes this year for the 25-year-old, and that's some feat.

Mickelson, the big man with the touch of a miniature portrait painter, very nearly sticks his chip in. But the disappointment on his face says it all, the game could be up. 'Only' a birdie, he's in the clubhouse on -15, one behind Rory McIlroy.

McIlroy did go for the green and found a bunker. A mixture of cheers from the more jingoistic American fans and groans from the more sympathetic. Here's Lefty...

It's getting grim out there, the light fading fast. Question is, will McIlroy have a dart at the green or lay up? It's Bernd Wiesberger to play first... 220 yards to the pin and he's tugged it in the bunker...

Mickelson will hope this is the penultimate bullet he has to fire today... not likely, he hasn't quite made the green and will need to chip in across the corner of the bunker. Fowler will have an eagle putt, his ball just clambering over that bunker. McIlroy's ball is well below his feet and he asks if he can play his second before the others have reached the green - once Mickelson is on, he will be allowed to do just that...

Earlier we told you the 18th hole was playing the second easiest on the course. Fittingly, as it looks set to hold the key for deciding our winner, it has since become the most straight forward.

As many as 44 birdies have been found on the final drag as well as two eagles. For the chasers, there is hope...