American Brooks Koepka powered his way to a first major title in record-equalling fashion as Tommy Fleetwood's brave US Open bid ended in disappointment.
Koepka carded a closing 67 at a windswept Erin Hills to finish 16 under par, matching the tournament scoring record set by Rory McIlroy at Congressional in 2011.
The big-hitting 27-year-old fired six birdies and a solitary bogey to finish four shots ahead of overnight leader Brian Harman and Japan's Hideki Matsuyama, whose closing 66 will take him to second in the world rankings.
Only McIlroy and Tiger Woods had previously finished double digits under par in the game's toughest test, while no runner-up had ever managed such a total.
Fleetwood, who had made the cut in just one of his previous seven major appearances, finished alone in fourth on 11 under following a final round of 72, with Rickie Fowler, Bill Haas and Xander Schauffele a shot further back in fifth.
Koepka, whose caddie Ricky Elliott is from Portrush in Northern Ireland, becomes the seventh first-time major winner in succession, a run stretching back to Jason Day's victory in the 2015 US PGA Championship.
And he succeeded as US Open champion his good friend Dustin Johnson, who missed the cut at Erin Hills but gave him a pep talk on the phone after Saturday's third round.
Koepka has been tipped for the top since winning three tournaments on the Challenge Tour in 2013 and the Turkish Airlines Open on the European Tour the following year on his way to being named rookie of the year.
In 2015 he won his maiden PGA Tour title in Phoenix and finished 10th in the Open at St Andrews and fifth in the US PGA at Whistling Straits.
Koepka was also tied for fourth in the US Open in 2014 - albeit 10 shots behind runaway winner Martin Kaymer - and shot 71 at Erin Hills in the 2011 US Amateur, although he failed to reach the matchplay stages.
Fleetwood, who was hoping to become the third English winner since 1924 after Tony Jacklin (1970) and Justin Rose (2013), began the day in a tie for second and made an encouraging start with a birdie from eight feet on the second.
However, the 26-year-old from Southport then bogeyed the sixth after hitting a poor chip across the green and dropped another shot on the eighth after firing his approach over the green.
"Just getting it wrong, aren't we," he said to his caddie Ian Finnis, who has been a major part of Fleetwood's revival after slipping to 188th in the world last September.
Fleetwood, who had also returned to his long-time coach Alan Thompson after an unsuccessful spell with Pete Cowen, bounced back in style with a superb approach to the ninth, a green labelled "a little iffy" by 2015 champion Jordan Spieth after his closing 69.
The resulting birdie reduced his deficit to playing partner Koepka to four shots, Koepka having followed birdies on the first and second with another from 35 feet on the eighth.
Koepka's three-putt bogey on the 10th gave the chasing pack renewed hope, but Fleetwood was unable to convert birdie chances from six feet on the 11th or twice the distance on the next.
Harman had been tied with Koepka after his birdie putt on the third did a full circuit of the hole before dropping in, but found heavy rough off the tee on the 12th to make only his third bogey of the week.
A three-putt bogey from Harman on the 13th left clubhouse leader Matsuyama as Koepka's nearest challenger, but the American promptly got up and down from a bunker on the 14th and holed from 12 feet for another birdie on the next.
And when he completed his hat-trick from 16 feet on the 16th, all that was left to decide was whether he would equal or break McIlroy's record.
American Justin Thomas equalled the lowest score in major championship history as England's Tommy Fleetwood remained in contention for a maiden major title in a pulsating US Open.
Thomas fired nine birdies and then an eagle on the 18th to card a nine-under-par 63 at Erin Hills, the lowest score in relation to par in tournament history - eclipsing the eight-under 63 by Johnny Miller to win at Oakmont in 1973.
That took the 24-year-old to 11 under and a share of second place with Fleetwood and Brooks Koepka, who both shot 68 to finish a shot behind leader Brian Harman, who compiled a flawless 67 as he bids to become the first left-hander ever to win the US Open.
Fleetwood had been tied for the lead after birdies on the first, eighth, 12th, 14th and 15th, only to bogey the last after following up a poor pitch by putting his birdie attempt off the green.
The 26-year-old from Southport was a lowly 188th in the world rankings last September but has reaped the rewards of returning to his former coach Alan Thompson and employing his friend Ian Finnis as his caddie.
He finished a shot ahead of world number one Dustin Johnson to claim his second European Tour title in Abu Dhabi in January, and could become the second English winner of the US Open in five years after Justin Rose's victory in 2013.
Fleetwood said: "It was a really good round of golf and you don't realise until you start talking about it that I hardly missed a shot all day."
Asked about the prospects of emulating 2013 champion Rose, the 26-year-old from Southport added: "It will change my life. I know that.
"I have pictured winning the US Open a lot of times before. Doing it all night is not going to help and not make any difference. It's just a question of concentrating on each day as it comes.
"Today I felt really good, played really well. If I wake up with the same feelings tomorrow I'm going to have a chance. Hopefully I do. I'll take it one step at a time.
"I don't think I could play any different or score any better than I have done. And you can't do anything about what anybody else is doing.
"If somebody shoots nine under tomorrow in the top few (as Thomas did on Saturday) then I'll have to shoot 10, I guess. But you can't do anything about that stuff. I've just got to keep going.
"This is my first time in contention in a major, so whatever happens I'll be doing my best and seeing how well I can finish. And that's all you can do. But it will be a pleasure to go out on a Sunday trying to win a major.
"It would be great to follow in Justin (Rose)'s footsteps. He's a good role model for English golf."
But compatriot Paul Casey's chances looked to have disappeared as he struggled to a third round of 75 to fall from a share of the halfway lead to a tie for 17th with Eddie Pepperell and Masters champion Sergio Garcia.
Amazingly, Thomas's score could have been even better if not for bogeys on the fourth and 10th, as well as a missed eagle putt from six feet on the 15th after he had driven the green on the 288-yard par four.
"The majors have a different feel and sound to the roars and to hear the crowd go crazy when I holed that putt on 18 was really cool," said Thomas, whose back-to-back wins in Hawaii in January included an opening 59 in the Sony Open.
"I'm not sure when it's going to sink in or when I'm going to realise what I did. I know one thing, if it happened tomorrow and the result is what I want it to be, then I'd probably have a little different feeling. But I'm just so excited to give myself a great chance to win this golf tournament.
"I felt like my game has been good enough to compete in the majors this year. So to be able to do so and have a chance tomorrow is just going to be great.
"I could not have hit that three-wood to the last (from 299 yards) any better if I tried, just a little high cut and I was very fortunate for the overnight rain for the ball to stay there.
"When I saw it was about seven feet away I knew maybe we had a chance of history."
American players fill 11 of the top 13 places on the leaderboard, with Rickie Fowler two shots off the lead after a 68 and Ryder Cup team-mate Patrick Reed two strokes further back.
Reed had faced a similar length putt to Thomas on the 18th to shoot eight under, but missed his birdie attempt and had to settle for a 65.
That was a 10-shot improvement on his second round and left the 26-year-old seeking to turn his Ryder Cup heroics into individual success.
Reed, who beat Rory McIlroy in the first singles contest at Hazeltine last year and was wearing the trousers from his Ryder Cup uniform on Saturday, said: "You always can take that fire from Ryder Cup and use it in other events.
"But you're talking polar opposites. You're talking one-on-one competition against 155. And because of that you can go out and play some great golf, but you have a bunch of guys out there that can play some good golf as well.
"I think the biggest thing is not getting ahead of yourself. Every time I've been in majors so far I've put so much emphasis on them and tried so hard at them that I kind of got in my way.
"And this week I've been working with my coach, just sitting there and thinking, all right, let's go out and try to make a good golf swing and try to make a good putt. And at the end of the day add them up and see how you do."
Four years after Justin Rose ended a 43-year wait for an English winner, Paul Casey and Tommy Fleetwood headed into the third round of the US Open at Erin Hills in a four-way tie for the lead.
Casey recovered from a triple-bogey on his fifth hole of the day to add a 71 to his opening 66 and set a clubhouse target of seven under par, which was later matched by Fleetwood and American duo Brooks Koepka and Brian Harman.
Fleetwood, who had made just one halfway cut in his previous seven majors, birdied the last to add a 70 to his opening 67, with overnight leader Rickie Fowler's 73 leaving him on six under alongside compatriots Jamie Lovemark and JB Holmes.
Hideki Matsuyama was part of a five-strong group a shot further back after a brilliant 65, the Japanese star racing to the turn in 30 and picking up another shot on the 13th before having to settle for five closing pars.
Casey's opening 66 had left him a shot off the pace and he swiftly joined Fowler in the lead with a birdie from close range on the 11th, his second hole of the day, only to bogey the next and run up a triple-bogey on the 14th.
The 39-year-old was only able to move his fourth shot a matter of inches in heavy rough over the back of the green on the par five, before hacking out sideways and taking three putts from just off the green.
However, after dropping another shot on the 15th, Casey regained his composure superbly to birdie the 17th and 18th, the latter being the second longest hole in major history at 676 yards.
And the former Ryder Cup player then made it five birdies in succession - just one short of the US Open record equalled by Adam Hadwin on Thursday - by picking up shots on the first, second and third.
"It feels good," said the 39-year-old, who has recorded three consecutive top-six finishes in the Masters but whose sole top-10 finish in 13 US Open appearances came at Oakmont a decade ago.
"It's not every day you enjoy a round of golf with an eight on the card, but I'm a pretty happy man.
"It was a good display, all my own fault, of what can happen if you get out of position on this golf course. Even just trying to take my medicine is very, very difficult. It's a good eight in the end.
"I lost a bit of skin out there. I got out of position, but it's the attitude, it's the grit that matters at the end of the week.
"I had been swinging it well and it felt really, really good a couple holes later to be picking the ball out of the hole for a birdie. Then clawed all the way back and actually picked up one more to the good by the time we were finished."
Asked if he would have been able to recover from such a mistake earlier in his career, Casey added: "In my good seasons, yes, but there have been times when I struggled, so probably not!
"I was upset with the score I had made, but it did not have any effect on my attitude or how I was going to then approach the rest of the round or the next shot. Part of that is just age and part I'll give credit to Johnny McLaren (his caddie), credit to my wife and my little boy."
On a crowded leaderboard, American amateur Cameron Champ - who turned 22 on Thursday - and Xander Schauffele were unlikely contenders on five under par alongside Matsuyama, Players Championship winner Si Woo Kim and Brandt Snedeker.
Masters champion Sergio Garcia was two shots further back following a 71, with England's Andrew Johnston on two under.
But for the first time since the rankings were introduced in 1986, none of the world's top three made the cut as defending champion Dustin Johnson joined Rory McIlroy and Jason Day in making an early exit.
McIlroy at least had the satisfaction of four birdies in his last six holes to improve by seven shots on his opening 78, while Day's 75 left him 10 over and world number one Johnson finished four over.
The cut fell at one over par to leave the entire field separated by just eight shots.
Rickie Fowler made light of the longest course in major championship history with a "stress-free" and record-equalling start to the 117th US Open.
Erin Hills had been set up to play to 7,845 yards in the first round, surpassing the record set at Chambers Bay in 2015 by 150 yards, but a combination of wide fairways and a course softened by previous thunderstorms helped Fowler card seven birdies in a flawless opening 65.
That equalled the lowest score in relation to par in the first round of a US Open, Jack Nicklaus and Tom Weiskopf having both shot 63 in the first round on the par-70 layout at Baltusrol in 1980.
"It's always cool to be part of some sort of history in golf, but I'd rather be remembered for something that's done on Sunday," said Fowler, who finished in the top five in all four majors in 2014 but has yet to win one of the game's biggest prizes.
"I didn't see seven under at the start of the week, but today is the best we are going to get. I just kept making putts when it mattered.
"It was nice. You don't get many rounds at the US Open that are stress-free. I knew I needed to drive it well and from there was just able to manage hitting and continuing to swing well and hitting good shots and rolling a couple in."
Fowler, 28, who was 25 over par for his previous four rounds in the US Open, ended the day a shot ahead of compatriot Xander Schauffele and England's Paul Casey, with Tommy Fleetwood, Brian Harman and Brooks Koepka a shot further back.
Lee Westwood, who is seeking his first major title at the 77th attempt, carded a 69 which was matched by compatriot Andrew Johnston, but defending champion and world number one Dustin Johnson struggled to a three-over-par 75.
And Rory McIlroy, who said players might as well "pack your bags and go home,'' if they could not hit the wide fairways, found just five of them and slumped to a 78, despite having eagled the second by driving the green on the 330-yard par four.
Casey has recorded three consecutive top-six finishes in the Masters, but has just one top-10 in the US Open in 13 attempts.
"I would have snapped your arm off for six under," said the 39-year-old, who chipped in for an eagle on the first and added six birdies and two bogeys.
"I watched Rickie this morning and was hoping and praying if I could get the same kind of conditions I would be half as good as Rickie Fowler, so to be right behind him I'm ecstatic.
"This was a fun low round. I don't know that I've ever played a US Open where I've had that much enjoyment."
Fleetwood has made the cut in just one of his seven major appearances to date, but the 26-year-old from Southport made an ideal start with a birdie on his opening hole and added four more in a brilliant putting display.
"The course was as receptive as it's going to be but I never really tried to make a birdie, they just seemed to happen along the way," said Fleetwood, who finished second behind Johnson in the WGC-Mexico Championship earlier this season and lost in a play-off in the Shenzhen International in April.
"But towards the end I holed some great putts for par. No matter how fast you start or how many birdies you make, the pars are the ones that keep you in it. You don't really think about shooting five under at the US Open. Seven under is ridiculous."
Westwood's 69 was just the third time the former world number one has broken 70 in the first round of the US Open, with his lowest score of 67 coming last year.
"I played great," said the 44-year-old, who shot 80 when playing with eventual winner Johnson in the final round at Oakmont. "I missed one fairway, one green and that was the double bogey (on the 12th).
"My short game was great at Wentworth (in the BMW PGA Championship) but my ball-striking is really coming back to its best now and if I keep going then there's no reason I can't be in contention on Sunday."
The dry weather meant that Phil Mickelson missed the US Open for the first time since 1993 in order to attend his daughter's high-school graduation.
Only a lengthy weather delay - and there have been several already this week - would have given the five-time major winner a chance of being at the ceremony and then flying by private jet from California to Wisconsin.
But when play started in perfect conditions, Mickelson informed USGA executive director Mike Davis he would not be able to compete and first alternate Roberto Diaz took his place. Diaz carded a level-par 72.
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