Rory McIlroy made a solid start at the Dubai Desert Classic as he attempted to turn his recent good form into victory at Emirates Golf Club.
The world number one has finished second in his last three events and was returning to the scene of his first professional win six years ago, where he has secured four consecutive top-10 finishes.
The Irishman is clearly comfortable around the lay-out and, after starting on the ninth, got off to a flying start with birdies on his first two holes and another on the 18th got him to the turn in 34.
He picked up another shot on three and was four-under through 13 holes, four behind early leader Nicolas Colsaerts.
The big-hitting Belgian also started on the back nine and a hat trick of birdies from 11 to 13 and two more on 17 and 18 saw him set a blistering pace. Further birdies followed on one, three and seven and Colsaerts was eight-under with two to play.
England's Andy Sullivan was a shot back through 13 after five birdies and an eagle on the par-five 18th with McIlroy then leading an intimidating looking group on four-under.
McIlroy's playing partner Martin Kaymer was also four off the lead alongside Lee Westwood who had played 12 holes.
Ryder Cup star Stephen Gallacher, South African Jake Roos and German Maximilian Kiefer were also all on four under midway through their back nines.