The 31-year-old was able to add only a 70 to his spectacular opening 62, but that was good enough to keep him on track for a sixth European Tour victory.
England’s Tommy Fleetwood, Scot Stephen Gallacher and Dane Thorbjorn Olesen share second place, but Lee Westwood has six shots to make up after a bitterly disappointing finish.
Westwood drove wildly into the sandy waste on the 359-yard 17th and double-bogeyed one of the easiest holes on the Emirates course where he has three times been a runner-up, then failed to get up and down from just over the last green and had to settle for a 71.
Gallacher was joint second with Westwood a year ago and kept alive his hopes of going one better by matching Sterne’s round. Olesen is seen as one of Europe’s brightest prospects. He has already secured a debut at the US Masters in April and a fortnight ago shared the runner-up spot with Justin Rose at the Abu Dhabi Championship.
“I believe in myself and want to achieve my own goals – that’s the biggest pressure,” the 23-year-old said after a 66 that began with four successive birdies and again did not contain a single bogey.