Jon Rahm birdied the final two holes to capture his maiden major title in a scintillating finish to the 121st US Open at Torrey Pines.
With Louis Oosthuizen clinging onto the lead down the stretch, Rahm holed a slick 25-foot putt for a three at the penultimate hole, and after a sensible splash-out away from the pin from a greenside bunker at the 18th, he was fist-pumping with delight once again after rolling in his fifth birdie putt of the day.
Rahm's sensational brace of birdies capped a closing 67 and swept him into the outright lead on six under, and Oosthuizen was unable to avoid crucial mistakes over the closing holes as he had to endure yet another runner-up finish in a major championship.
It was a fitting finale to an enthralling final day on the southern California coast, with the top of the congested leaderboard packed with star names as Rory McIlroy, Bryson DeChambeau, Brooks Koepka and Justin Thomas forced their way into contention before falling away over the back nine.
DeChambeau looked a smart bet to retain his title when he came within an inch of making a hole-in-one at the eighth and led by one with eight to play, but he bogeyed 11 and 12 and then slipped when launching his drive away at the 13th, blocking it way right and needing four to find the green before three-putting for a double-bogey seven.
His misery was compounded at the 17th, where he ran up a quadruple-bogey eight, while McIlroy was left to reflect on yet another story of what might have been, having also enjoyed a share of the lead only to three-putt for bogey at the 11th before his second to 12 plugged on the downslope in a bunker to the right of the green, leading to a horrible six.
With Koepka also unable to maintain his challenge for a third US Open win as he bogeyed two of the last three, the list of genuine contenders was whittled down to Oosthuizen and Rahm, who set his stall out with birdies at each of the first two holes before giving one back at the fourth.
He enjoyed a huge slice of good fortune at the ninth, where he pulled his drive left and it was initially thought his ball had finished on the wrong side of an out-of-bounds fence, but he was soon taking a free drop in the rough after consulting a tournament official.
Rahm took full advantage of the lucky break as he layed up and clipped a wedge to three feet to set up and birdie which took him to the turn in 33, and he kept his composure in check to grind out seven straight pars before his birdie-birdie finish piled the pressure on Oosthuizen.
Determined to avoid his sixth runner-up finish in a major championship, the 2010 Open winner had a two-shot lead when he made back-to-back birdies at the ninth and 10th, only to block his tee shot to the short 11th and make his second bogey of the day.
Oosthuizen holed clutch putts for pars at three of the next six holes, but his error off the tee at the 17th left him needing an eagle at the last to force a playoff, and after finding the lush rough on the left with another errant drive, he decided to lay up from just under 250 yards and take his chances at pitching in while Rahm kept himself loose on the range.
But the long-odds ploy was beyond his reach, leaving an emotional Rahm to celebrate his first major title with his wife and new baby, and a return to the top of the world rankings - a remarkable case of atonement following his dramatic enforced withdrawal from The Memorial a fortnight ago.
To his credit, Oosthuizen holed from 10 feet at the last to get back to where he started the day on five under, two ahead of a fast-finishing Harris English, who birdied three of the last five to claim his first podium finish in a major, having finished tied for fourth at Winged Foot last year.
Although the Molinari brothers both enjoyed encouraging first rounds, it was Guido Migliozzi who would fly the flag for Italy as he matched the 68 of English to close on two under alongside Koepka and last year's PGA champion, Collin Morikawa.
Koepka raised the prospect of a playoff with arch-rival DeChambeau when he turned in 32 and recovered from a blemish at 12 with birdies at 13 and 15 to get to four under, but the two-time champion pulled his tee shot to the 16th and made a mess of the final hole, making bogeys at both to return a 69.
As Rahm accepted the trophy and attributed his victory to "the power of positive thinking", McIlroy struggled to hide his despondency having failed to capitalise on arguably his best chance to end his seven-year wait for a fifth major title.
McIlroy displayed the same resolve that was a highlight of his third-round 67 as he plotted his way cautiously through the outward nine, carding eight pars around a 40-foot birdie putt at the fourth, but his three-putt bogey at 11 was followed by two bad breaks at the next.
With his second plugged on the downslope of the bunker to the left of the green, a stab-shank with his third found the thick rough on the left of an adjacent trap and he needed three more to get down.
He revived his fading hopes with a birdie at the long 13th, but those hopes ended when he bunkered his tee shot to 16 and bogeyed again before he parred in for a 73 to finish on one under with Paul Casey, whose superb 67 was the joint-low round of the final day.
As for DeChambeau, his series of big mistakes added up to a back-nine of 44, leaving him to sign for a 77 which looked a remote prospect when he was tied for the lead during the early stages of a memorable conclusion to the US Open.