The 29-year-old had started his day three shots behind overnight leader Padraig Harrington, but played a near faultless round, including eight birdies, to storm to the top of the leaderboard for a 17-under-par 271 total.

His only blot, however, could have been a crucial one.

Casey failed to make a relatively simple putt on the 18th and had to settle for a bogey.

That threatened to let nearest rival Miguel Angel Jimenez force a play-off, but the Spaniard carded a bogey on the 17th and could only make par on the last to finish a shot behind in second place and hand a relieved Casey the trophy.

"As far as professional rounds go, it was probably my finest final round," said Casey. "I played some really good golf at the HSBC Match Play, but that is not the same situation.

"I was pushed all the way. Every birdie I made I felt Miguel (Angel Jimenez) and Padraig (Harrington) were right behind me making birdies as well.

"It is nice when you are pushed - I always think it is easier to chase, but it was by far my best final round of golf.

"At the beginning of the week I genuinely wanted to see if I could win one of the three tournaments in the Middle East, but to win the first one is beyond my expectations."

A victory on the Abu Dhabi Golf Course By Sheraton seemed a long way off after the first round, when Casey carded a disappointing one-under-par 71.

But a four-under 68 on Friday set the 2006 golfer of the year up for an impressive weekend when he carded 67 and 65 respectively.

He added: "The first round was fairly slow, it was tough day. One under is not great golf, but from there my game just kicked off.

"I struggled round this golf course last year, not a lot has changed, there are a couple of new tees and a few new bunkers, but apart from that it is pretty much the same golf course.

"I am ecstatic that I got better every single day and to finish it off with a 65, despite a blemish on the last, I am very happy."

In contrast, European Tour Order of Merit winner Harrington failed to build on his confident display on Saturday to fall away and in the end offered little threat to Casey.

The Irishman made three birdies on the first nine but endured a disappointing run coming home when he carded two bogeys and pars on the rest of the holes to finish 4th at 14 under.

"It was a poor start," said Harrington. "I suffered with my focus. I bogeyed two holes on the back nine and that doesn't happen too often. Such is the game.

"It is always disappointing when you have a chance but I still feel I am ahead of expectation for this time of the year."

ALL THE FINAL ROUND SCORES

(Gbr & Irl unless stated, par 72)

271 Paul Casey 71 68 67 65

272 Peter Hanson (Swe) 70 68 66 68, Miguel Angel Jimenez (Spa) 71 65 68 68

273 Chris DiMarco (USA) 69 70 68 66

274 Retief Goosen (Rsa) 66 72 68 68, Jean-Francois Lucquin (Fra) 70 69 67 68, Padraig Harrington 68 67 68 71

275 Henrik Stenson (Swe) 66 72 70 67

276 Robert Jan Derksen (Ned) 70 69 69 68, Phillip Price 69 65 71 71, 277 Gary Orr 70 68 70 69, Nick Dougherty 66 72 70 69, Phillip Archer 63 75 71 68

278 Robert Karlsson (Swe) 73 67 69 69, Sergio Garcia (Spa) 68 72 69 69, Stephen Dodd 69 70 72 67, Colin Montgomerie 69 71 69 69, Alastair Forsyth 71 66 69 72, Thongchai Jaidee (Tha) 68 71 67 72

279 Steve Webster 70 73 69 67, Shiv Kapur (Ind) 70 66 68 75, Paul Lawrie 67 72 69 71, Marcel Siem (Ger) 71 72 67 69, Kyron Sullivan 72 71 70 66, James Hepworth 68 71 68 72, Graeme Storm 68 70 69 72, Richard Sterne (Rsa) 70 67 71 71, Andrew McLardy (Rsa) 70 72 70 67

280 Anthony Wall 68 75 66 71, Christian Cevaer (Fra) 73 68 71 68, Niclas Fasth (Swe) 71 69 73 67, Richard Green (Aus) 67 72 69 72, Emanuele Canonica (Ita) 70 73 68 69, Raphael Jacquelin (Fra) 70 71 68 71, Ian Garbutt 69 74 69 68

281 David Carter 71 68 71 71, Gary Murphy 72 68 68 73, Garry Houston 70 67 71 73, Julien Guerrier (Fra) 68 72 69 72, Alejandro Canizares (Spa) 75 68 70 68

282 Graeme McDowell 71 72 69 70, Alessandro Tadini (Ita) 70 66 71 75, Oliver Wilson 70 72 73 67, Maarten Lafeber (Ned) 71 70 71 70, Nick O'Hern (Aus) 68 68 75 71, Peter Hedblom (Swe) 71 69 72 70

283 Damien McGrane 72 68 71 72, Thomas Bjorn (Den) 71 71 71 70, Gregory Bourdy (Fra) 70 73 72 68

284 James Kingston (Rsa) 71 68 70 75, Soren Hansen (Den) 73 69 69 73, Alvaro Quiros (Spa) 70 70 75 69

285 Juan Parron (Spa) 71 71 70 73, Brett Rumford (Aus) 70 70 72 73, Stephen Gallacher 70 73 71 71, Andrew Marshall 73 70 73 69, Miles Tunnicliff 72 71 73 69, Oliver Fisher 68 71 73 73

286 Mark Pilkington 73 70 69 74, Robert Rock 69 72 71 74, Matthew Millar (Aus) 73 69 75 69, David Park 73 70 71 72, Chinarat Phadungsil (Tha) 71 71 73 71, Kenneth Ferrie 74 68 75 69, Gary Emerson 67 70 74 75

287 Francesco Molinari (Ita) 69 71 74 73, Soren Kjeldsen (Den) 75 68 71 73, Benn Barham 75 67 72 73

288 Yasin Ali 71 70 71 76, Notah Begay III (USA) 72 71 74 71, Terry Price (Aus) 74 69 71 74, Ariel Canete (Arg) 68 74 74 72, John Bickerton 74 68 72 74

289 Markus Brier (Aut) 73 69 73 74

291 Lee Slattery 71 70 76 74