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.
15. Dezember 2018
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|Real Valladolid 2 Atletico Madrid 3: Griezmann the hero on landmark appearance|
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|Gibson has no worries over Proteas batsmen|
|Wolves 2 Bournemouth 0: Jimenez and Cavaleiro score against toothless Cherries|
|Crystal Palace 1 Leicester City 0: Captain Milivojevic earns vital victory|
|Watford 3 Cardiff City 2: Hornets hang on despite late fightback|
|Tottenham 1 Burnley 0: Eriksen snatches victory at the death|
|Huddersfield Town 0 Newcastle United 1: Rondon strike settles scrap|
|Sabres suspend forward Berglund for failing to report to the team|
|Saunders thanks Fury for getting him ´back on the right track´|
|Hannover 0 Bayern Munich 4: Gnabry and Kimmich star in crushing win|
|I admire Sterling – Guardiola|
|City´s strength in depth makes it hard for me – Jesus|
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|Kashima Antlers 3 Guadalajara 2: Comeback win sets up Real Madrid semi-final|
|Hosszu claims fourth Hangzhou gold, Le Clos beaten by Santos|
|Manchester City 3 Everton 1: Jesus at the double as City go top|
|Parker defiant on low blow claims after ending 2018 ´with a bang´|
|Alisson: Liverpool must beat Manchester United|
|Mourinho´s brutal honesty praised by Karanka|
|Fielding inspired by Bellew after overcoming setbacks to face Canelo|
|Mourinho loves being a manager ´more than ever´|
|Khawaja unconcerned by poor start to India series|
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|Christmas form could transform Man United´s season - Rashford|
|Urgent changes needed at Manchester United – Ferdinand|
|Ishant confident as Kohli carries India into day three|
|Modric takes aim at Simeone for ´constantly undermining Real Madrid´|
|Kevin Durant provides playoffs warning to inconsistent Warriors|
|A-League Review: Janjetovic off as Wanderers suffer derby defeat|
|VanVleet turnover the ´turning point´ in Raptors loss|
|Shanahan on Mahomes no-look pass: ´I do it all the time´|
|De Bruyne and Aguero return to City bench, Sterling left out of starting XI|
|Kohli and Rahane combine to thwart Australia in Perth|
|Modric cool on Madrid future beyond current deal|
|´Fatigued´ Embiid has a lot on his shoulders - Brown|
|Crespo agrees to take charge at Banfield|
|Westbrook on Murray scuffle: He was in my way|
|Liverpool v Manchester United: Van Dijk the rock on which Klopp can build a title triumph|
|Marcelo ´never´ considered Madrid exit amid Juventus links|
|Liverpool v Manchester United: Resurgent Rashford now a leader for Mourinho|
|Injury-plagued Nuggets beat Thunder to hold Western Conference lead|
|Southee takes five as Sri Lanka recover in Wellington|
|Kings troll Curry by playing clips of moon landing|
|Guardiola: Premier League title race similar to Barca-Madrid battles|
|Ovechkin joins rare NHL club with second straight hat-trick|
|Liverpool can´t be judged just on trophies – Klopp responds to Mourinho|
|Athletics´ Chapman undergoes procedure on left shoulder|
|Marcelo: Real Madrid miss Ronaldo|
|Ronaldo right about Juventus team spirit – Allegri|
|Klopp: I´m not the pope of football tactics|
|Stade beat Ospreys on emotional Chauvin tribute night|
|Ligue 1 survival bid a marathon not a sprint for Monaco, as club appoints distance runner|
14. Dezember 2018
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|De Bruyne injuries could be a blessing for City, says Guardiola|
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|Ulster complete Scarlets double, Exeter gain Gloucester revenge|
|Sheffield United 1 West Brom 2: Baggies comeback boosts automatic promotion push|
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|Canelo v Fielding: Rocky ready to write his own fairytale in New York|
|Boca part company with Schelotto after Copa Libertadores loss to River|
|Canelo v Fielding: Tale of the tape|
|Juventus defender Cancelo has knee surgery|
|Canelo v Fielding: Alvarez and Rocky make weight in New York|