Karlsson shot a sublime seven-under-par 65, bogey-free final round for an aggregate of 15-under-par 273, while last year’s winner Quiros shot a 67 for a total of 12-under-par 276.
England’s Lee Westwood and Australian Brett Rumford were a shot behind in joint third with 11-under-par 277. England’s Oliver Wilson (71) finished with three birdies in a row to share fifth at eight-under-par 280 along with overnight leaders Bradley Dredge of Wales and Paul Casey of England.
Karlsson, who was two shots off the pace set by Dredge after the third round on Saturday, virtually steamrollered the field on the final day as his rivals failed to exploit perfect golfing conditions at Doha’s only championship course.
The 40-year-old, who became the first Swedish player to capture the Harry Vardon Trophy as Europe’s number one in 2008, suffered a frustrating 2009 when he missed several months of action due to blurred vision in his left eye caused by fluid build-up in his retina.
But yesterday the Monaco resident produced near-flawless golf to pick up three birdies on the front nine and four, including two consecutives ones on the final two holes to comfortably win his first title in 16 months.
Karlsson’s last title came at the Dunhill Links Championship in October 2008.
“It was a tough time coming back,” said Karlsson.
“I had a couple of good finishes at the end of last year with Henrik (Stenson) at the World Cup and with a second in Japan, but it is fantastic to be back now.
“I am really happy to be back playing well, it is the first time I have played really well for a long time and the way I finished off today was very satisfying.”
Karlsson was engaged in an engrossing duel with Westwood for the title but the Englishman’s hopes vanished on the 16th hole which he bogeyed after a string of four birdies on the 10th, 11th, 13th and 14th holes.
However, in the final analysis, it was his poor front nine, during which he had three bogeys that put paid to his hopes of winning his first title in Doha.
Westwood’s lacklustre final round helped Quiros the most as the Spaniard played steadily to finish second.
Quiros, who was three shots adrift after the third round and had given up hope of winning the title saying all he could hope for was a decent finish, was surprised by his second place finish.
“Yeah, this is better than what I expected,” said Quiros, one of the longest hitters in the game.
“Really, I was very lucky – I holed a 30m putt on the ninth and chipped in twice so I am very pleased even though I was just a few centimetres away from an eagle on the last,” added Quiros.
“But it’s a good defence. I was looking for a top five finish so I have to be happy.”
Westwood said he was not pleased with his driving. “I struggled with the driver, once I smashed the face in yesterday and I think I hit two fairways after that with the driver, which is not like me at all,” said Westwood.
“So every credit to Robert – I hit some good shots coming in and got within one of him. But then he hit a good shot into fourteen and finished with a couple of birdies for the grand slam finish so he’s a deserved winner.”