The winds were the strongest they had been all week, but Lawrie stayed consistent throughout his round, with birdies at the 14th and 18th holes.
The Scot made the European Ryder Cup team in both previous years he won in Qatar and a third victory would put him in contention for another appearance in the biennial team event in 2016.
"There's a lot of good players behind me. Branden Grace is obviously defending champion, won here before and well up the world rankings," Lawrie said on the European Tour website.
"So tomorrow is going to be a different challenge but I'm looking forward to it."
Spain's Rafael Cabrera-Bello and Britain's Tommy Fleetwood are a further shot behind on 10 under par.
(Writing by Toby Davis in London; editing by Andrew Roche)