Martin Kaymer put himself on course for a fourth Abu Dhabi HSBC Championship title after a second consecutive 66 lifted him into the halfway lead.
Kaymer struggled over the early stages of his second round, but an eagle at the eighth revived his challenge and he carded six birdies in a superb inward 31 as he closed on 12 under par, one clear of his Ryder Cup team-mate Rafa Cabrera Bello.
Overnight leader Henrik Stenson's lack of practice heading into the Desert Swing suddenly became apparent as he slipped three off the pace after an untidy 71, while defending champion Rickie Fowler and US Open holder Dustin Johnson recovered from their disappointing opening rounds with 68s to make the cut with plenty to spare.
Kaymer parred the first five holes and then bogeyed the sixth, but he got back on track with two mighty blows to find the green in two at the 497-yard eighth and his 20-foot eagle putt found the target.
The German began the back nine with birdies at 10 and 11 only to give another shot back when he carelessly three-putted the 12th, but he atoned with a nice three at 13 and then produced a superb chip-in for his fourth birdie in five holes at the next.
Kaymer then got a 40-foot putt to drop for an unlikely birdie at the 16th, and the three-time winner capped an excellent day's work with a four at the last to replace Cabrera Bello as clubhouse leader.
Cabrera Bello made the most significant move of the early starters when, after starting at the 10th, he made four birdies in five holes from the 12th before the putts dried up in a run of seven straight pars.
The Spaniard then made his only bogey of the day at the sixth, but he hit back with three consecutive birdies to close out an impressive 66 which swept him to 11 under.
Tommy Fleetwood kept a blemish off his card in a classy five-birdie 67 which earned him a share of third with Kiradech Aphibarnrat (68) and Paul Dunne, who was one of only four players to make eagle at the 18th while he also had five birdies in a confident 66.
Stenson, who opened with a flawless 64, appeared likely to extend his overnight two-shot lead when he birdied the first, although he dropped his first shot of the week at the third before responding with further birdies at the fourth and eighth.
But the Swede got into trouble at the 10th and ran up a scrappy six which he followed with another bogey at the next, and he could not better par at the next six holes before his birdie at the last got him under the card for the day.
Tyrrell Hatton is alongside the Open champion at nine-under after returning a solid five-birdie 68, while Lee Westwood is two further adrift and was visibly frustrated at three-putting the 18th green in a disappointing finish to his 69.
Fowler reeled off four straight birdies around the turn but could not maintain his momentum and settled for a 68 along with compatriot Johnson, who handed in a bogey-free card.
But Masters champion Danny Willett (76) and DP World Tour Championship winner Matt Fitzpatrick (75) will both have the weekend off along with Ryder Cup sensation Thomas Pieters, who added a lacklustre 72 to his opening 73.