A brilliant back nine from Tiger Woods helped seal his seventh victory in eight outings as Ernie Els let a fourth Dubai Desert Classic title slip from his grasp.

The world number one trailed the South African by four shots when he bogeyed the ninth with Els, a three-time winner in Dubai, a four groups behind.

But a remarkable turnaround saw Woods card six birdies coming home, which included a crucial 25-foot putt at the last, as he covered the back nine in just 31 to complete a round of 65 and set the mark at 14 under.

Els was one stroke behind but had three holes in which to find at least one birdie to force a play-off but his ambition proved to be his downfall as he dumped his approach to the par-five 18th in the water as he attempted to reach the green in two.

That cost him any chance of victory and a bogey six meant he signed for a one-under 71, which dropped him back into a share of third place with compatriot Louis Oosthuizen on 12 under.

Abu Dhabi champion from three weeks ago Martin Kaymer finished runner-up a shot adrift of Woods after an impressive final-round 66.

After winning the Buick Invitational by eight strokes last week, Woods collected his second victory in Dubai and his 82nd career triumph and has been pleased with his early form in 2008.

"It's an ideal start to the year. To go two for two is a pretty good start," Woods said.

"I felt good with my putting stroke. On Saturday it was a touch off but I feel like I rolled the ball well today and all week I've had good pace.

"When you have good pace you can read the greens and I was reading them pretty good all week."

Woods topped the leaderboard for the first two days but slipped four shots adrift of overnight leader Els after a frustrating third-round 73.

He began the final day with three birdies in his first four holes but reached the turn just one under for his round after bogeys at six and nine, three-putting the latter.

But after clawing back a shot at the 10th there followed three successive birdies - sparked by a chip-in at the par-four 12th - to lift the American to 12 under.

Woods picked up another stroke at the 17th before that crucial birdie at the last when he sank a tough 25-foot downhill putt - having bogeyed the hole yesterday by hitting his second into the water.

The world number one was then forced to watch as Els headed down the last with a birdie required to force a play-off but the South African's 240-yard three-wood approach caught the wind and came up short in the water.

Woods admitted he had some sympathy for Els after he had a similar - although not as catastrophic - experience the previous day.

"People don't realise how much the wind blows on the grandstand over the 18th. If you just up shoot it a touch the wind will just smoke it and that's what happened to me yesterday," Woods added.

"I got off to as good as start as you possibly could, I was three under through four but dropped shots at six and nine and I went from being in the mix to being out of the mix.

"I told my caddie (Steve Williams) if we shoot 30 on the back nine maybe we will be in a play-off.

"I shot 31 and it happened to be good enough. I like winning by seven or eight it's less stressful.

"Ernie had a pretty tough shot at the last; I've been there before I put the ball in the water on the last hole with a chance to win the tournament."

Els played a solid front nine and two birdies meant he reached the turn at 13 under for the tournament.

However, by then Woods' charge was well under way and missed par putts from inside five feet at 11 and 12 cost the South African dearly.

Back-to-back birdies followed to set-up a thrilling climax but Els could not find the one birdie he needed over the closing three holes to force a play-off and, to add insult to injury, his missed eight-foot par putt at the cost him a share of second place.

"It was a little disappointing. I played really solid on the front nine but it could have been four or five under," said Els, who has now finished inside the top three in each of his last seven visits to Dubai

"Those two putts really cost me the tournament in the end because I played really solid coming in."

Collated final round scores & totals

(Gbr & Irl unless stated, par 72):

274 Tiger Woods (USA) 65 71 73 65

275 Martin Kaymer (Ger) 67 73 69 66

276 Ernie Els (Rsa) 68 72 65 71, Louis Oosthuizen (Rsa) 73 69 69 65

278 Graeme McDowell 67 72 69 70

280 Soren Hansen (Den) 68 72 70 70, Ricardo Gonzalez (Arg) 72 71 72 65, Peter Hedblom (Swe) 69 70 70 71, Henrik Stenson (Swe) 68 70 68 74

281 Ross Fisher 69 70 71 71, Niclas Fasth (Swe) 72 71 70 68, Lee Westwood 69 71 68 73, Thomas Levet (Fra) 67 71 72 71

282 Jean-Baptiste Gonnet (Fra) 72 68 72 70, Gary Murphy 67 72 71 72, Scott Hend (Aus) 67 72 72 71, Paul McGinley 71 72 69 70, Bradley Dredge 73 72 68 69

283 Jeev Milkha Singh (Ind) 67 76 69 71, Anthony Wall 73 72 68 70, Robert Karlsson (Swe) 70 70 73 70, Hennie Otto (Rsa) 69 70 72 72, Sergio Garcia (Spa) 68 71 70 74, Thongchai Jaidee (Tha) 69 73 70 71

284 Shiv Kapur (Ind) 68 72 69 75, Brendan Jones (Aus) 71 71 74 68, David Frost (Rsa) 72 69 69 74, Simon Dyson 67 77 67 73, Paul Broadhurst 70 71 69 74

285 Ariel Canete (Arg) 68 75 72 70, Gonzalo Fdez-Castano (Spa) 73 71 72 69, Peter O'Malley (Aus) 68 73 70 74

286 Soren Kjeldsen (Den) 69 74 71 72, Miles Tunnicliff 69 74 70 73, Marcus Fraser (Aus) 69 75 70 72, Johan Edfors (Swe) 71 70 73 72, Richard Sterne (Rsa) 69 75 71 71, Jyoti Randhawa (Ind) 67 74 75 70

287 Mark O'Meara (USA) 70 74 73 70, Ian Poulter 70 71 70 76, Jean Van de Velde (Fra) 73 72 72 70, Phillip Archer 72 72 74 69, Andrew McLardy (Rsa) 67 74 73 73

288 Damien McGrane 68 69 72 79, Mikko Ilonen (Fin) 74 71 68 75, James Kingston (Rsa) 68 74 75 71, David Howell 68 75 72 73, Pelle Edberg (Swe) 67 74 71 76, Maarten Lafeber (Ned) 71 72 71 74, Stephen Gallacher 70 73 71 74, Thomas Bjorn (Den) 74 70 73 71, James Kamte (Rsa) 74 71 71 72, Gregory Havret (Fra) 72 71 72 73

289 Robert Jan Derksen (Ned) 68 75 71 75, Steve Webster 73 71 71 74, Alexander Noren (Swe) 71 71 71 76, Martin Erlandsson (Swe) 72 72 71 74, Miguel Angel Jimenez (Spa) 67 74 73 75, Simon Khan 72 73 70 74, Jose Manuel Lara (Spa) 70 74 73 72

290 Anders Hansen (Den) 70 74 72 74

291 Benn Barham 68 74 74 75, Per-Ulrik Johansson (Swe) 71 74 74 72, Graeme Storm 69 72 75 75

292 Colin Montgomerie 72 72 73 75, Andrew Coltart 69 71 72 80

295 Stephen Dodd 73 72 73 77

296 Garry Houston 68 77 78 73

299 Daniel Vancsik (Arg) 68 77 75 79