Sami Välimäki closed with a 69 on Sunday thanks to a birdie at the penultimate hole to reach 18-under and enter a playoff against Spain's Jorge Campillo who carded a 70.
Campillo parred the first extra hole while the Finn birdied for his second DP World Tour title.
"Unbelievable," said Välimäki. "It's hard to talk. It's been a long journey and it feels great.
"I've worked so hard and I feel like I've earned it a couple of times but it hasn't come my way. That's why it feels so amazing."
Scotland's Scott Jamieson and Spain's Nacho Elvira both shot 69s to finish third at 16-under.
Jamieson's finish was good enough to move into the top 116 on the Race to Dubai Rankings and retain his playing privileges for next season.
"I'm delighted, obviously," said the Scot. "Not the best situation starting the week.
"I'd spent the whole year on the right side of the line and then as each week went on and on, I kept missing the cuts by a shot.
"I spent a lot of Friday afternoons watching the scoreboards to see if I was going to sneak in. I think that was probably half my problem - I was just trying to make cuts and keep my head above water.
"Then all of a sudden this week, it's a very different game. I've got to have a result. I knew in my mind it was top-20 minimum or it won't be good enough. It's just amazing what a better mindset can do."
England's Jordan Smith closed with a 68 to finish in solo fifth place at 15-under.
