Briton Paul Lawrie, who led the tournament after three rounds, slumped to a fourth-round 78 to finish well down the field
South African Branden Grace shot a composed final-round 69 on Saturday to become the first player to retain the Qatar Masters title.
The 27-year-old conjured up four birdies to finish on 14 under par, two strokes ahead of Spaniard Rafael Cabrera-Bello and Dane Thorbjorn Olesen.
"It's a dream. This is a tournament that kicked my season off last year and hopefully it can take me to even better things this time round," Grace, who has now won seven European Tour titles, told the Tour website.
"The key was my grinding and staying patient. It was tough out there, but fair. I knew if I stuck to my guns and tried to give myself some opportunities, I could do it."
Briton Paul Lawrie, the former British Open champion who led the tournament after three rounds, slumped to a fourth-round 78 to finish well down the field.