Ireland's Shane Lowry recovered from a sluggish start to remain the man to beat at the halfway stage of the Abu Dhabi HSBC Championship on Thursday.
After matching the course record with a splendid 62 on the opening day, Lowry lost the lead with two bogeys in his opening three holes as he was made to pay for poor shot selection.
However, the three-times European Tour winner soon rediscovered his groove to roll in four birdies as he finished with a two-under-par 70 and a one-shot advantage at the top of the leaderboard.
"I'm really happy with that," said Lowry. "I knew today was going to be a bit of a weird day after shooting such a low score yesterday."
"Some of the shots early on were pretty horrendous. I battled back and hit some really nice shots out there and hit some in close and made some birdies."
Lowry missed a six-foot birdie opportunity on his final hole but finished his round 12-under overall, a shot ahead of South Africans Louis Oosthuizen and Richard Sterne heading into Friday's third round.
Oosthuizen, who has finished no worse than seventh in his last three starts, began brightly with three birdies on the front nine but lost momentum when he sent his ball into a bush at the 10th hole.
The 2010 British Open winner did not let that setback derail his challenge as he notched back-to-back birdies at the 13th and 14th.
A lucky break when the ball bounced off a bunker ensured Oosthuizen closed the round with a tap-in birdie for a 68 to join a bogey-free Sterne on 11-under.
"Trying to win any event and going into the weekend really close, it's always exciting," Oosthuizen said.
England's Lee Westwood is two-shots off the pace in fourth place after carding a bogey-free 68.
It has not been so straightforward for his compatriot Tommy Fleetwood, who held his nerve for a birdie at the 18th to make the cut.
The 27-year-old is chasing his third straight title but he remains nine shots off the pace after a round of 72.
World number two Brooks Koepka is five off the pace after a scrappy 70 which included a closing bogey, while his compatriot Dustin Johnson is three further back after a 71.