Welsh rookie Rhys Davies shot a final round 66 to earn his maiden European Tour victory by two strokes at the Hassan II Trophy in Rabat, Morocco.
Davies, 24, trailed overnight leader Louis Oosthuizen by three with 15 to play but went on to make eight birdies to claim the £207,666 first prize.
"It's all a bit surreal to me", said Davies who ended with a 25-under total.
South African Oosthuizen paid for two bogeys on the back nine as he shot a 70 to record his fourth runners-up finish.
France's Thomas Levet (71), Spaniard Ignacio Garrido (70), Miko Ilonen (66) of Finland and another South African, Thomas Aiken (71), were tied for third, another five shots back.
Former Walker Cup player Davies, who came third in the Malaysian Open a fortnight ago, began the day two shots behind 27-year-old Oosthuizen.
And he dropped another shot behind when he bogeyed the par-three second.
However, that proved a mere blip as a birdie on the fourth put the Bridgend golfer back on course before he picked up three more strokes at the sixth, seventh and eighth.
Oosthuizen had two birdies on the front nine as the gap narrowed to one stroke in what was developing into an intriguing matchplay-type duel between the pair.
Davies, a graduate from last year's Challenge Tour, went in front with birdies on the 10th and 11th only for his rival to reassume the ascendancy with an eagle on the par-five 12th.
Bogeys at the 14th and 15th, though, saw Oostuizen, who has never won a Tour event, once again flounder in a final round.
In contrast, Davies held his nerve, picking up shots at the 13th - with a 22-foot putt - and the 206-yard 14th before holding par on the final four holes to see out the victory.
"I didn't really think very much out there. It was all a bit of a blur," said former British boy champion Davies.
"I just felt I could make every putt and felt in control of my swing. That was the best I've hit it all week."
Of the chasing pack, Ilonen made the most dramatic surge up the leaderboard, with eagles on the eighth and 10th helping him match Davies's and Christian Nilsson's round of the day 66.
England's Danny Willett, 22, followed his excellent third-round 64 with a 71 to tie for fourth overall alongside compatriot Robert Rock (70) and Swede Nilsson.
Irishman Peter Lawrie shot 67 to finish a further shot back on 15 under.
In-form Davies, meanwhile, could eventually come into the reckoning for Europe's Ryder Cup team ahead of this October's tournament in Wales's Celtic Manor.
But he said: "That's way out of my equation at the moment. This is the first win, hopefully the first of a few, and it's really special."