Vancsik closed with his third 4-under 68 of the week to complete his first tour win at 18-under-par 270. His total of 270 tied the tournament scoring record that Des Smyth set in 2001.
The Argentine had previously not finished better than tied for 16th on the European Tour.
'It was a surprise to me to play so well this week,' admitted Vancsik. 'But when you feel good with your putting and your short game, which my new coach has helped me with, you can relax on the course.'
Santiago Luna, who got as close to Vancsik as anyone on Sunday (six shots), carded a 3-under 69 to share second place at 11-under-par 277. He was joined there by David Frost, who shot 68 on Sunday. Christian Cevaer, Euan Little and Mads Vibe-Hastrup shared fourth place minus-9.
Vancsik got off to a flying start with birdies on two and three to move to 16 under. He stumbled to a bogey on three, but his lead was still six strokes.
The 30-year-old pushed that lead to seven strokes as he ran off three straight birdies from the seventh. The only reason his lead wasn't nine shots was the fact that Luna matched Vancsik's birdies on seven and nine.
Vancsik put things out of reach for good as he collected back-to-back birdies from No. 11 at Santo da Serra Golf Club. For the week, Vancsik played the par-5 11th at minus-5 with three birdies and an eagle.
Owning an eight-stroke lead with six holes to go, Vancsik cruised to the house. He did trip to bogeys at 13 and 15, but there was plenty more room for error. Vancsik parred his final three holes to close out the win.
'Vicente Fernandez has helped me a lot with my game, but I have a lot to thank Angel Cabrera and Ricardo Gonzalez for,' stated Vancsik. 'Angel has been text messaging me every day to advise me. He and Ricardo had told me all about the course and staying patient, which helped me a lot this week.'
Luna, the 1995 champion, was even-par through six holes before running off four birdies in a five-hole span from the seventh. That got Luna to 12 under, but he was still eight back. He stumbled into the house with a birdie and two bogeys over his final seven holes.
Frost looked like he was going to make a run at the top spot with four front-nine birdies, but he was side tracked by a triple-bogey on four. He birdied 10 and 11 to get to 10 under. Frost dropped a shot on 13, but birdied 15 and 18 to climb into a share of second place.
Alexander Noren, Gregory Bourdy and Simon Nash tied for seventh place at 8-under-par 280. Francesco Molinari, who won the Italian Open last year, ended one shot further back at minus-7.