Rory McIlroy remains on track to end a 14-month European Tour title drought after shooting a second round 70 to lead the $2.5 million |Omega Dubai Desert Classic on Friday, while world number one Tiger Woods toiled on the Majlis course.
McIlroy reached the event's halfway stage 11 under at 133, having done most of the hard work a day earlier with a first-round 63.
He is one shot ahead of the United States' Brooks Koepka, who followed his first-day 69 with a 65.
Scoring on Friday proved tougher for most players as Thursday's lush greens dried out under the unforgiving Gulf sun, with the Northern Irishman's playing partners Woods and Stephen Gallacher shooting 73 and 71 respectively.
That left Woods on 141 and defending Dubai champion Gallacher on 137 and outsiders for the $417,000 first prize.
McIlroy, whose last tour victory was at 2012's DP World Tour Championship also in Dubai, began inauspiciously, pulling his opening drive into the rough and then fluffing a 12-feet par putt for his first bogey of the tournament.
The world number six's tee shots were also wayward on the next two holes, but a sumptuous bunker shot allowed him to sink a three-foot birdie putt at the third.
The 24-year-old picked up another shot on the fifth as he made his first fairway of the round and reasserted his grip on the tournament with a five-foot birdie at the seventh and another at the 10th.
Two bogeys at 13 and 16 threatened to pull the former US Open champion back into the pack, but a birdie on the last gave him some narrow breathing space going into Saturday's third round.
Woods rarely sparkled, hitting the fairway on only four occasions and failing to take the more difficult birdie opportunities he would have sunk in his pomp, although he did end a run of 11 successive pars with a birdie at the third.
A scuffed seven-footer at the sixth and another fluffed putt at the ninth led the 14-times Major winner to drop two shots and he did little on the back nine, whose three par-fives and two par-threes usually offer more opportunities to pick up shots.
Rory McIlroy endured a frustrating day on the greens at the Dubai Desert Classic on Friday, but he still reached the tournament's halfway stage with a one stroke lead.
The Ulsterman struggled off the tees early on in his second round, but by the turn he had briefly eased three strokes clear of the field, only for his putting woes and a charge by rising US star Brooks Koepka to keep him in check.
McIlroy had a 70 to stand at 11-under 133, with Koepka, a year younger than McIlroy at 23, equalling the day's best round of 65 to get to 10 under.
Two strokes further back on eight under came Damien McGrane (70) of Ireland, Englishman Danny Willett (65) and Julien Quesne of France (70).
Defending champion Stephen Gallacher of Scotland (71) and European number one Henrik Stenson of Sweden (67) were among those on seven under.
It was another disappointing day for Tiger Woods, who struggled with the putter all the way en route to a 73, which left him eight shots adrift of playing partner McIlroy and well down the field.
Looking to make it two wins and a second place in his last three tournaments, McIlroy had the luxury of taking the morning off watching to see whether anyone could overhaul him after his stunning nine-under 63 on Thursday.
Several challengers came and went, especially McGrane, Willett and Italian Ryder Cup star Edoardo Molinari.
But no-one was able to dislodge McIlroy from the lead.
For a brief moment it looked like he would do that all by himself as he started his second round with three wayward drives.
He dropped one at the first, but scrambled to save par at the second, and a superb bunker shot at the par-five third gave him a birdie as he got back to nine under.
Watched by wife-to-be, tennis player Caroline Wozniacki, McIlroy then birdied the fifth and the seventh to increase his lead at the top to three shots.
But just when it looked like he was about to clamp a serious stranglehold on a tournament which was his first triumph as a professional in 2009, McIlroy let it briefly slip - missing a two-footer for par at the 13th and erring off the tee at the 16th.
Koepka, who opted to play on the European Tour Challenger circuit after graduating from his US college in May, 2012, was flawless with seven bogeys in his 65.
Woods, playing in his second tournament of the year after missing the final cut at Torrey Pines last week, never looked like getting fully into his stride, despite an encouraging birdie at the third.
Bogeys at six and nine set him back and from there on in he was unable to get any momentum going in a tournament he has twice won.
World number three Stenson moved ominously up the leaderboard as he recovered from a horror start to Thursday's opening round when he was three over after just five holes.
The big Swede had five birdies in his 67 that hoisted him up the leaderboard at seven under.
Three-time former winner Ernie Els was also in better nick with a 70, but at level par for the tournament, the South African was just outside the projected cut mark.
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