Lucas Bjerregaard fired a final round of 67 to overhaul defending champion Tyrrell Hatton and win the Alfred Dunhill Links Championship.
Hatton looked in a strong position to win the tournament for a third straight year after back-to-back scores of 66 left him in the lead heading into Sunday's play at St Andrews.
The Englishman - fresh from helping Europe win the Ryder Cup in France - reeled off four successive birdies on his front nine to remain in control, only to suffer a surprising collapse after the turn.
He had back-to-back bogeys at the 10th and 11th before dropping further shots at the 15th and 16th, leaving him to sign for a level-par 72 and a share of second place with Ryder Cup team-mate Tommy Fleetwood.
Bjerregaard, who had trailed by as many as six shots with 12 holes to play, finished one ahead of the big-name duo to secure his second European Tour title and move into the top 10 in the Race to Dubai rankings.
"It didn't really look like I was in it today - Tyrrell looked like he was going to take off with it," the delighted Dane told Sky Sports.
"I'm really happy now. It's been a great year, but now it's got a whole lot better."
The 27-year-old crucially bounced back from bogeying the penultimate hole with a three at the par-four last, with Hatton - bidding to become the fifth player to win the same event in three consecutive seasons - unable to force a play-off when he failed to find the cup with a birdie putt of his own on the 18th green.
"I guess my putt on the last to get in the play-off sums it up, really. Just a massive gust of wind knocks me off, pretty much lose balance on a putt, which is unfortunate," a dejected Hatton told the European Tour's website.
"I'm pretty disappointed because I had a five-shot lead at one point. It was in my hands."
Fleetwood had set the clubhouse target at 14 under by signing for a 69, though it could have even better for the Englishman had he taken a birdie opportunity on the final hole.
Tapio Pulkkanen of Finland was alone in fourth on 12 under while American pair Brooks Koepka and Tony Finau both finished inside the top 10, ending on nine and eight under respectively.
|Sri Lanka hand England their heaviest ODI defeat|
|Nuggets guard Will Barton undergoes surgery|
|Surprise package Svitolina closes in on semi-final berth|
|Alexander-Arnold targets glory at home and abroad|
|Pogba relishing emotional Juventus reunion|
|Alba hopes Lopetegui keeps Real Madrid job|
|Valverde not expecting Messi magical recovery|
|Wozniacki calms fears over knee injury|
|Maybe it´s my interviews - Klopp on Liverpool´s room for improvement|
|Language no barrier to Dortmund dangermen Reus and Alcacer|
|EPCR confirms no replay of Bath-Toulouse Champions Cup fixture|
|F1 Raceweek: Five the magic number as Hamilton eyes Mexico repeat|
|RFU to introduce in-season breaks for players|
|Nainggolan misses Barcelona trip|
|Wozniacki battles through knee complaint to down Kvitova|
|Alcacer: Two seasons at Barcelona not lost|
|Henderson, Keita to miss Liverpool´s Red Star clash|
|Khabib holds talks over Mayweather Moscow fight|
|Wolf in for Titz as Hamburg try to stop slump|
|Davies released from Wales squad as Evans comes in|
|Mbappe on track to match Messi and Ronaldo, says Giuly|
|Coleman, Kipchoge and Lyles among IAAF Male World Athlete of the Year shortlist|
|Serena Williams will win slams again sooner or later, says Seles|
|You always want the best – Ter Stegen open to Neymar return|
|Xavi: My teams will never use Mourinho´s style|
|I knew what I got myself into - LeBron appreciates Lakers are a work in progress|
|Mourinho: Ronaldo loves United but he will want to score|
|Cooper completes Rebels move and takes parting shot at Reds coach Thorn|
|Bellerin amazed by ´born champion´ Ozil|
|Penguins, kangaroos and ´Stone Cold´ Steve Austin: Halloween comes early for Trail Blazers|
|Ronaldo gunning for United, Aguero targets double record - Champions League in Opta numbers|
|Ill Vardy couldn´t stomach penalty decision – Puel|
|LeBron´s Lakers lose again, Magic stun Celtics|
|Bartomeu: No Barca return for Neymar, Valverde contracted until 2020|
|Simmons and ´stimulating´ 76ers in NBA Finals mix, says Longley|
|Falcons heap further misery on Giants|
|Vidic hails Ronaldo as ultimate professional ahead of Old Trafford return|
|Warriors´ Cousins nearing NBA return|
|Pogba can´t do the basics – Souness criticises Man United star|
|Messi absence big blow for Barca as Icardi talks up Inter|
|´You can´t cry, that´s true´ – Ronaldo responds to Isco|
|Bartomeu: Barca still competitive without Messi|
|Bills RB McCoy remains in concussion protocol|
|Raiders place Marshawn Lynch on IR|
|Emery calm over title talk after another Arsenal win|
|Green: Warriors have to clean up defensively|
|Mariners say Bolt talks ongoing amid reports contract offer was rejected|
|Proud captain Ozil revels in Arsenal´s ´sexy football´|
|Puel angry over Holding handball|
|Cilic breezes through in Basel, Anderson fights back|
|Ingram: Four-game ban better than we expected|
|Raiders send Cooper to Cowboys for first-round pick|
|Arsenal 3 Leicester City 1: Outstanding Ozil inspires comeback win|
|World Series 2018: Three reasons why the Dodgers will win|
|Yarmolenko out for six months after Achilles surgery|
|World Series 2018: Three reasons why the Red Sox will win|
|Ozil eclipses Klinsmann to become Premier League´s most prolific German|
|Allegri expecting Old Trafford battle against Mourinho´s United|
|Bertens feared she did not belong in Kerber clash|
|Returning Ronaldo expecting ´tough´ game against Manchester United|
|Cristiano Ronaldo confident of clearing his name amid rape allegation|
|Osaka looking to learn from losing start in Singapore|
|Kovac expects tough test against AEK Athens|
|Whyte gives Chisora deadline over rematch|
|Spartak Moscow sack Massimo Carrera|
|Atletico Madrid confirm fresh injury issue for Gimenez|
|Dolberg extends Ajax contract after Real Madrid links|
|Ronaldo an example for Lukaku to follow|
|Bertens battles back to blast past Kerber|
|Ramos apologises for training ground fracas|