Swede Richard S Johnson sank a 30 foot birdie putt on the final green to become only the second home winner of the Nordea Scandinavian Masters in the last 12 years.
With a play-off looming against Argentina's Rafa Echenique, the 33 year old looked to have played safe with his approach to to the 407 yard last at Bro Hof Slott near Stockholm.
But months of putting problems in America - he is now based there, but has not had a single top-30 finish since February - were forgotten as he took his second European Tour title eight years after his first.
Johnson, whose regular caddie Lance Ten Broeck went and played in The Senior Open Championship presented by MasterCard instead, earned €333,330 after a closing 71 gave him an 11 under par total of 277.
"It's one of the sweetest things I've ever done," he said. "Just to come up the 17th and 18th is magical.
"This is a huge tournament to win for a Swede and I'm speechless right now. It's epic."
Italian Edoardo Molinari, winner of The Barclays Scottish Open two weeks ago, finished third thanks to a 20 foot last putt.
That left Open Championship winner Louis Oosthuizen in a tie for fourth with Australian Brett Rumford and New Zealander Mark Brown.
"I didn't play well," said Oosthuizen after his 73. "I didn't drive well and it put everything under pressure.
"I had to push it at the end, but Richard played brilliantly. I'm a bit disappointed, but after last week I was hoping to make the cut and I finished fourth, so I'm happy."
He now heads back home for a week off and a party at his home club to celebrate his Major victory.
With joint overnight leader K J Choi hooking his opening drive out of bounds and then putting two balls in water for a nine on the 15th - the Korean eventually signed for a 78 - the day eventually developed into a battle with World Number 329 Johnson and World Number 371 Echenique.
Others had chances, though. Belgian Nicolas Colsaerts, five behind at the start, led when he turned in 32, but then came home in 40.
Molinari, meanwhile, said after his 69: "I missed so many putts. I think I could have won easily to be honest.
"But that's golf sometimes. I'm still outside The Team [or The Ryder Cup], so I need to play well in the last two or three events."
A second place finish would have put him fourth in the standings and would have put Luke Donald out of the all-important top nine, although the English star had a chance to improve his hopes of a recall in Canada later in the day.
Choi's double bogey seven on the first gave Johnson a two shot lead, but he bogeyed the next two and after regaining a one stroke lead he bogeyed the short 16th to drop back alongside Echenique.
The South American won The European Tour's Shot of the Year for a closing albatross in Germany last season, but he finished runner-up in that event as well and this was his third second place finish.
The 29 year old had a lot of positives to take from the week, though - just not as many as Johnson.
