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.
|´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|
|Vertonghen eyeing Spurs future beyond 2020|
|De Bruyne injuries could be a blessing for City, says Guardiola|
|Emery prepared to face Arsenal´s centre-back crisis|
|Ulster complete Scarlets double, Exeter gain Gloucester revenge|
|Sheffield United 1 West Brom 2: Baggies comeback boosts automatic promotion push|
|Del Potro back on court following knee injury|
|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|
|Spalletti does not fear another mid-season crisis at Inter|
|Salah headlines CAF Player of the Year shortlist as Koulibaly misses out|
|Beckham Jr. out of Titans clash|
|Lipsky hits the front at Leopard Creek|
|Pederson coy over Wentz back injury|
|Liverpool ´not really likely´ to be active in January window, reveals Klopp|
|Always on the move and unpredictable - Pavard reveals surprising choice over toughest opponent|
|We need to get back to respect - Lampard alarmed by hate in football|
|Giles returns to England to replace Strauss as director|
|Hansen has no issue with Milner-Skudder Toulon switch|
|Juventus to rest Ronaldo after Torino showdown|
|Titmus strikes gold again as world records tumble in Hangzhou|
|Malinga to captain Sri Lanka in New Zealand|
|Rivaldo would like ´excellent´ Isco at Barcelona|
|United a long way from Mourinho´s vision|
|´Klopp denies an answer!´ - Liverpool boss dismisses questions about ´world-class´ Pogba|
|Returning Nowitzki ´so tired´ after making NBA history|
|Aguero and De Bruyne in contention for Manchester City v Everton|
|Simeone has no plans to cash in on Costa|
|Canelo v Fielding: Alvarez´s greatest nights|
|Fabregas: Chelsea being unfairly scapegoated over racism allegations|
|Crisis? What crisis? Klopp focuses on defensive solutions for United clash|
|Hope cannot inspire Windies as Bangladesh cruise to series win|
|Benitez picks up Premier League Manager of the Month award|
|Chavez, Marquez and Canelo - Mexico´s greatest multi-weight world champions|
|Bale set to miss Real Madrid v Rayo Vallecano|
|Robben out until January as Bayern look to avoid serious injury|
|Milan avoid UEFA ban in FFP punishments.|
|Mourinho compares Liverpool to ´an amazing house´ but insists trophies matter|
|Brisbane Roar 2 Melbourne Victory 4: Muscat´s men hit A-League summit|
|Bumrah confident second Test is ´in the balance´ after India recovery|
|Isco gesture was for a corner or foul, claims Solari|
|Harris leads Australia into ascendancy on day one|
|ATP announces candidates to host future Finals|
|Ronaldo: Juventus fans refuse to lose to Torino|
|Hero Rivers feared he had cost Chargers in KC|
|Williams would welcome Llorente back to Athletic Bilbao|
|Liverpool v Manchester United: Minding the gap|
|Milan elimination unjust, fumes Leonardo|
|Paul hails ´sick´ Harden after record-breaking display|
|Liverpool v Manchester United: Salah, Mane and Firmino v Rashford, Martial and Lukaku in Opta number|