Rory McIlroy completed his amazing 70-day transformation from Masters meltdown to major marvel by winning the US Open by a dream-like eight shots over Australian Jason Day.

The wonder kid from Holywood in Belfast delivered the golfing equivalent of a Hollywood blockbuster, setting record after record at Congressional as he kept the trophy not just in European, but Northern Irish hands.

More than that, he became at 22 the second youngest European major winner of all time - and the youngest since 1872, the year Young Tom Morris captured his fourth and final Open at 21. He died three years later.

"The whole week has been incredible - I could not have asked for any more and I am so happy to hold this trophy," he said.

"For such a small nation to win two US Opens in a row is pretty special. As Graeme (McDowell) said last year, there will be a lot of pints of Guinness going down.

"I know a few of my friends will be partying and I can't wait to get home and join them."

On his recovery from The Masters he added: "Augusta was a valuable experience. I knew what I needed to do today to win. I learnt a few things there about myself and my game.

"I put a few different things into practice and it paid off."

Not since amateur legend Bobby Jones in 1923 has this the toughest of all four majors been lifted by someone of such tender years - and with Padraig Harrington saying that McIlroy has the potential to challenge Jack Nicklaus's 18-major record it ought to be noted that the Golden Bear was a few months older when his first win came.

But the most remarkable thing is that it was only in April that McIlroy imploded at Augusta, seeing a four-stroke lead turn into a 10-shot defeat with a closing round of 80.

This was the first major since then and he was a class apart from the moment he started in the same way he had at The Masters with a 65.

By the time he had raised his arms in triumph to the roars of the crowd - such a contrast to the heckling that runner-up Colin Montgomerie received at the same venue in 1994 - everybody present knew they had witnessed something and somebody truly special.

Among the first to join in the celebrations was his dad Gerry. On Father's Day that was only right and proper.

"Happy Father's Day - this one's for you," shouted McIlroy at the presentation ceremony. "I have to mention my mum too - everything they have done for me I can't thank them enough."

Back at home there were the same joyous scenes that had greeted McDowell's victory 12 months ago - the first by a European in the event for 40 years.

They have all known about McIlroy's talent since he shot 61 at Portrush as a 16-year-old - and many of them for long before that.

With a closing 69 for a tournament record 16 under par total of 268, these are the new US Open marks he set or shared - and whether he goes on to do more than Nicklaus or Tiger Woods, who won by 15 in 2000, should not detract from this achievement:

Lowest halfway total - 131

Biggest halfway lead - 6 (with Woods)

Lowest 54-hole total - 199

Quickest to 10 under - 26 holes

Quickest to 11 under - 32 holes

Quickest to 12 under - 34 holes

First to 13 under - 35 holes

First to 14 under - 50 holes

First to 15 under - 55 holes

First to 16 under - 58 holes

First to 17 under - 64 holes

Most under par 72 holes - 16 under

Lowest 72-hole total - 268 (by 4)

He also became only the third player to have four rounds in the sixties at the event and while those statistics, inevitably, also said something about how soft the Washington course was all week, it was the same for everyone and only one took full advantage.

Insistent that he had his Masters nightmare in context within a few days of it happening - he was third in Malaysia the following Sunday - a visit to earthquake-hit Haiti the week before coming to Washington added further perspective.

He still had to show, however, that regardless of his eight-stroke cushion with a day to go he was capable of remaining in a league of his own.

Lee Westwood, joint third overnight, started with a birdie, but in the group behind McIlroy matched it from nine feet and an approach to four feet at the 470-yard fourth made the gap double figures.

YE Yang got it back to eight on the two outward par fives and McIlroy had a narrow escape when his pitch to the long sixth only just made it over the water, actually bouncing off the wall of the water onto the green.

Asia's only major winner - he overtook Woods at the 2009 US PGA - then struck his tee shot to around three feet on the dangerous short 10th, but McIlroy not only got inside him, but almost holed-in-one.

Sharing it in birdie twos meant he was a step closer and McIlroy had, of course, improved five shots on what he took at Augusta's 10th that fateful day.

When Yang hit his second into water on the 11th and bogeyed victory seemed in the bag and, as if it had not been all weekend, the real battle was for second place.

And, as at The Masters, 23-year-old Day ended up as runner-up, a bogey-free 68 seeing him finish two ahead of Westwood, Korean YE Yang and little-known Americans Robert Garrigus and Kevin Chappell.

For Westwood, who mixed three birdies with three bogeys for a 71, his wait for a first major goes on - and he did not quite do enough either to regain the world number one spot from Luke Donald.

McIlroy did bogey the 12th after driving into sand and, after another birdie at the long 16th, he did have his only three-putt on the 17th.

But it was all over long before then. The future of golf had arrived.

Collated final-round scores (USA unless stated, par 71):

268 Rory McIlroy (NIrl) 65 66 68 69

276 Jason Day (Aus) 71 72 65 68

278 Robert Garrigus 70 70 68 70, Kevin Chappell 76 67 69 66, Y.E. Yang (Kor) 68 69 70 71, Lee Westwood (Eng) 75 68 65 70

279 Peter Hanson (Swe) 72 71 69 67, Sergio Garcia (Spa) 69 71 69 70

280 Charl Schwartzel (Rsa) 68 74 72 66, Louis Oosthuizen (Rsa) 69 73 71 67

281 Davis Love III 70 71 70 70, Heath Slocum 71 70 70 70, Brandt Snedeker 70 70 72 69

282 Fredrik Jacobson (Swe) 74 69 66 73, Graeme McDowell (NIrl) 70 74 69 69, Bo Van Pelt 76 67 68 71, Matt Kuchar 72 68 69 73, Webb Simpson 75 71 66 70

283 Steve Stricker 75 69 69 70, Johan Edfors (Swe) 70 72 74 67

284 Ryan Palmer 69 72 73 70, Patrick Cantlay 75 67 70 72

285 Dustin Johnson 75 71 69 70, Robert Rock (Eng) 70 71 76 68, Bill Haas 73 73 68 71, Retief Goosen (Rsa) 73 73 71 68, Brandt Jobe 71 70 70 74, Gary Woodland 73 71 73 68, Henrik Stenson (Swe) 70 72 69 74

286 Rory Sabbatini (Rsa) 72 73 70 71, Seung-yul Noh (Kor) 72 70 73 71, Zach Johnson 71 69 72 74, John Senden (Aus) 70 72 72 72, Harrison Frazar 72 73 68 73, Do-hoon Kim (Kor) 73 71 70 72, Kyung-Tae Kim (Kor) 69 72 69 76, Ryo Ishikawa (Jpn) 74 70 74 68, Gregory Havret (Fra) 77 69 71 69

287 Sung-hoon Kang (Kor) 74 72 70 71, Martin Kaymer (Ger) 74 70 72 71, Adam Hadwin (Can) 75 71 73 68

288 Russell Henley 73 69 71 75, Lucas Glover 76 69 73 70,Sang-moon Bae (Kor) 75 71 75 67

289 Robert Karlsson (Swe) 79 67 71 72, Charley Hoffman 71 74 75 69, Michael Putnam 74 71 73 71, Luke Donald (Eng) 74 72 74 69, Padraig Harrington (Irl) 71 73 72 73, Chez Reavie 70 75 72 72

290 Alexander Noren (Swe) 75 67 74 74, Marc Leishman (Aus) 73 69 72 76, Scott Piercy 73 71 76 70

291 Phil Mickelson 74 69 77 71, Anthony Kim 74 72 75 70, J J Henry 72 73 76 70, Matteo Manassero (Ita) 74 72 73 72, Alvaro Quiros (Spa) 70 71 72 78, Edoardo Molinari (Ita) 74 70 74 73

292 Justin Hicks 74 71 76 71, Marcel Siem (Ger) 79 66 74 73, Todd Hamilton 73 72 77 70

293 Bud Cauley 71 72 74 76, Jeff Overton 72 72 74 75, Brian Gay 73 71 74 75, Bubba Watson 71 75 74 73

295 Kevin Streelman 73 73 74 75

296 Kenichi Kuboya (Jpn) 73 73 74 76

297 Alexandre Rocha (Bra) 69 76 76 76, Christo Greyling (Rsa) 72 74 75 76

303 Wes Heffernan (Can) 75 71 79 78

305 Brad Benjamin 72 73 80 80