The Dane had entered day four a shot behind Wilco Nienaber and with the duo clear of the rest of the field, a two horse race soon developed at Randpark Golf Club.
The local favourite turned in 32 to open up a three shot lead heading into the back nine but Hansen displayed nerves of steel as he birdied the tenth, 12th and 14th to fight his way back to the top of the leaderboard at 19 under.
Nienaber got a remarkable break as his ball stayed dry on the par three 17th but he could not take advantage, and Hansen parred his way home to win by two shots and become a European Tour champion in his 146th appearance.
South African Shaun Norris carded a closing 66 to finish at 16 under, with another home favourite in Brandon Stone, Canada’s Aaron Cockerill and England’s Steve Surry six shots off the lead.
There were tears in Hansen’s eyes after he holed the winning putt to complete a long journey to European Tour victory ten years after turning professional.
He graduated from the European Challenge Tour in 2012 and 2015 but had a breakout year in 2018, claiming two Challenge Tour victories en route to becoming the first Dane to top the Rankings since Thomas Bjørn 23 years earlier.
The 30-year-old had his best year to date on the Race to Dubai in 2019 as he finished in the top 50 on the Rankings presented by Rolex and, after securing an impressive top ten in the Rolex Series at the BMW PGA Championship last month, he is now a winner, making it a Danish hat-trick in 2020 after Rasmus Højgaard’s brace of victories.
“It’s quite emotional,” he said. “This is what we work for, you know? The family watching back home.