Henrik Stenson, the overnight leader, dropped three shots at the 13th and 14th holes to fall off the pace, but made things interesting in the end. He birdied three of his last four holes, but needed an eagle at 18 to force a playoff. Stenson posted a 1-under 71 to take second at minus-11.
'I'm happy with the way I finished. I fought well and I have to say it was a fantastic round by Ernie,' said Stenson, a two-time winner on the European Tour. 'I knew he would be chasing. I hit a couple of bad shots at the 13th and just missed my drive on 14th and the double bogey was crucial. I was pleased that I was able to regroup and almost birdied the last three holes for a playoff.'
For Els, this is his second win in as many weeks. He captured last week's Dubai Desert Classic and polished off the 'Middle East Slam' on Sunday. This was Els' 20th win on the European Tour and moved him to first on the Order of Merit.
'I really feel good,' said Els. 'My rhythm feels really good at the moment and I'm in a good position at the top of the backswing. When that happens, I can freewheel it and go for the ball. My iron play was a lot better. I feel like my game is right there and I can't wait to get to America now.'
Richard Green also needed an eagle at the last to match Els at minus-12, but he bogeyed the closing hole at Doha Golf Club. Green carded a 1-under 71 and joined Pierre Fulke, who shot a final-round 70, in third at 9-under-par 279.
Els trailed Stenson by five at the start of the final round, but Els steadily moved up the leaderboard. Els traded a birdie and a bogey over his first three holes, but collected three birdies in a row from the fourth to get within four of the lead.
Els, a three-time major winner, birdied the 10th and 12th holes to trail by a stroke from Stenson, as the Swede found trouble with a bogey at 10. Stenson bogeyed the 13th and Els birdied the 16th to grab the lead. Stenson double-bogeyed 14 after a bad drive and now Els was two ahead of Green and three up on Stenson.
The South African birdied the 18th to get into the clubhouse at 12 under par. Stenson birdied 15 and 16 to trail by two and had a look at birdie from 25 feet at the 17th. His putt skirted the edge of the hole and his chip for eagle at the last did not fall, giving Els the victory.
'One hundredth of an inch at the 17th cost me the chance of a playoff,' admitted Stenson, who earned his third top 10 of the season. 'I was certain that putt had to go in.'
Since the putt did not fall, Els became the first player on the European Tour to win in back-to-back weeks since Vijay Singh titled at the Carlsberg Malaysian Open and the Caltex Masters in 2001.
'I wanted to give myself a low score and as it turned out I shot low which you don't normally do,' admitted Els. 'I got lucky and got a win. I must say the middle of the front nine when I made three birdies was big as the wind was really playing up at that time.'
Robert Karlsson (70), James Kingston (69) and Barry Lane (71) shared fifth place at 8-under-par 280. Gregory Havret (71), Raphael Jacquelin (70) and Louis Oosthuizen (68) tied for eighth at minus-7.
Niclas Fasth was tied for second after 54 holes, but struggled on Sunday. He double-bogeyed his second and third holes en route to a 4-over-par 76 and a share of 16th at minus-4.