Donaldson opened the day two strokes behind Justin Rose, who had three bogeys in a 1-under 71 in the final round. A bogey at the 16th hole put Donaldson ahead by two and allowed him to withstand a 72nd-hole bogey and collect his second European Tour title.
Donaldson wound up 14-under 274 with Rose and Thorbjorn Olesen, who shot a final round 69, both one stroke back at 13-under.
Ricardo Santos was 4-under Sunday and finished in fourth at 11-under. Branden Grace closed with four consecutive birdies for a 7-under 65 and a fifth-place finish overall at 10-under. Grace had 10 birdies and three bogeys Sunday.
Olesen was tight to the lead after back-to-back birdies on Nos. 4-5 but had a double bogey 6 at the sixth hole and dropped back. David Howell also made a charge, getting to 5-under on the day through 10 holes but a bogey at 12 and a triple-bogey 7 at 13 left him out of contention.
Rose had a second-hole birdie but posted bogey on No. 5. Donaldson, meanwhile, used birdies at 1 and 9 to pull into a tie for the lead. Rose's bogey at 11 put Donaldson alone in first. Rose kept pace with birdies at 12 and 14 while Donaldson had birdies at 14 and 15, dropping putts of 18 and 15 feet.
Rose had trouble on 16 and missed a 12-foot par putt, putting Donaldson ahead by two. Donaldson did have a bogey 6 at the 18th hole but Rose closed with two pars.