David Lingmerth emerged victorious from a titanic battle with Justin Rose to clinch his maiden PGA Tour title after an enthralling final day of The Memorial at Muirfield Village.
Lingmerth closed with a resolute three-under 69 and then held his nerve to edge out the overnight leader with a par at the third extra hole following a pair of outstanding par saves from both combatants at the 18th.
Rose was a firm favourite at the start of the day having opened up a three-shot lead with a third-round 66, but he struggled with inconsistency throughout the final 18 holes and ultimately did well to salvage a level-par 72.
The Englishman dropped four shots in six holes on the outward nine, although birdies at the fifth and ninth limited the damage to a 38 before he regained the outright lead with further birdies at 11 and 13.
He then bogeyed the next after being rattled by a heckler while splashing out from a greenside bunker, and he got the shot back at the 15th before missing the green at 16 and dropping back to 14 under.
But Rose nailed a superb putt for birdie at 17, although he pushed a three-wood into a fairway bunker at the last and shanked an eight-iron from the sand - hitting an unfortunate spectator on the head and knocking him over.
However, a clearly shaken Rose regained his composure to play a sublime pitch to four feet which he converted to match Lingmerth, who looked out of contention until he bounced back from a bogey at 10 with three birdies in five holes before parring in to return a 69 and take over the clubhouse lead from Jordan Spieth.
Rose then holed a brilliant, 20-foot curling putt for par at the first extra hole and Lingmerth followed him in from the fringe to extend the contest, and the Swede got up and down from a greenside bunker to match Rose's solid par in their second effort at the 18th.
Trouble at the 10th
They then moved to the 10th, where Rose pushed another drive into thick rough behind a tree while Lingmerth striped his down the centre and knocked his approach to 30 feet.
Rose sent the galleries scurrying for cover again as he went long and left with a pulled hybrid before his tricky pitch rolled 15 feet past the pin and he was unable to escape with a par.
Lingmerth knocked his birdie putt five feet past the cup, but he calmly knocked in the return to earn the biggest payday of his career and an invaluable two-year exemption on the PGA Tour.
Masters champion Spieth enjoyed the clubhouse lead for over two hours after he carded six birdies and an amazing chip-in for eagle at the 15th as he closed with a 65 to set the target at 13 under par.
Francesco Molinari put himself on course for a maiden win on US soil when he reeled off three straight birdies from the third to replace Rose as leader, but the Italian made a dreadful misjudgement at the short 16th as his tee shot came up short and found the water.
The mistake cost him a double-bogey six, and he was unable to find a birdie at each of the two closing holes as he settled for 71 and a share of third with Spieth, while defending champion Hideki Matsuyama, Jim Furyk and Marc Leishman completed excellent weeks on 12 under par.
England's Andy Sullivan was unable to find the form that carried him to a tournament-best 64 in round two, although a closing 73 earned him a creditable share of 13th place on nine under.