However, the four-time major winner holed from 30 feet to salvage a bogey and take a one-shot lead up the 18th, which proved just enough to secure his fourth win of the year after Sullivan’s birdie attempt narrowly missed.

A closing 66 saw McIlroy finish 21 under par at Jumeirah Golf Estates, one shot ahead of Sullivan with South African Branden Grace a distant third on 15 under.

McIlroy missed three tournaments this summer, including the defence of his Open title at St Andrews, due to an ankle injury suffered playing football with friends and needed a controversial exemption to compete in the European Tour’s season finale despite not playing enough events.

Nearest rival Danny Willett felt that gave McIlroy an unfair advantage but was unable to dislodge the four-time major winner from top spot in the money list, a position he held since finishing fourth in the Masters before winning the WGC-Cadillac Match Play three weeks later.

Willett had to settle for a six-way tie for fourth on 13 under which included Italy’s Francesco Molinari, who recorded a hole-in-one on the sixth in a final round of 68.

Sullivan held a one-shot lead overnight and extended it to three with birdies on the first and second as McIlroy followed a birdie on the second with a three-putt bogey on the fourth.

McIlroy bounced back in style with birdies on the fifth and sixth but Sullivan followed the four-time major winner in on each occasion to maintain his advantage as he looked to claim a fourth European Tour win of the season.

Another birdie from McIlroy on the seventh finally closed the gap and Sullivan’s lead looked set to be wiped out when he bogeyed the eighth and saw his escape from a fairway bunker on the ninth catch the edge of the trap.

The 29-year-old then hit his third shot over the green but chipped in for the most unlikely of pars, much to the delight of his 30-strong personal fan club who had travelled from Nuneaton to support him this week.

McIlroy must have been wondering what he had to do to catch Sullivan after he holed from 12 feet for a birdie on the 11th, only to see his playing partner follow him in for the third time.

That scenario looked set to be repeated on the 12th when McIlroy holed from 25 feet, but Sullivan’s birdie attempt narrowly missed and the pair were tied on 20 under with six holes to play.

McIlroy finally got his nose in front by pitching to three feet to birdie the par-five 14th, the first of five holes he birdied in succession to lift the title and become European number one for the first time in 2012.

And the former world number one looked in ruthless mood as he carded his eighth birdie of the day on the next to move two shots clear with just three holes to play, only to throw the £5.2m event wide open once more on the 17th.