Lee Westwood fired a five-under-par 67 to charge into the lead after the third round of the Dubai Desert Classic.
The Englishman, 40, moved to 15 under, one shot ahead of Scotland's Stephen Gallacher, Germany's Marcel Siem and Spain's Rafael Cabrera-Bello.
Northern Ireland's world number two Rory McIlroy, who shared the lead overnight with Thomas Bjorn, only managed a par-72 and remains 13 under.
Bjorn dropped threes shots in the last four holes and fell back to 12 under.
World number three Westwood's 67 added to Friday's 65 and his first-round score of 69 as he came from three shots behind to lead in the desert.
His third-round total contained seven birdies and two bogeys.
McIlroy's level-par round saw him go into the water on the 18th, and featured three bogeys in his last four holes.
The US Open champion and winner of the title three years ago did hole three birdies in the back nine.
Gallacher and Siem carded rounds of 68 and first-round leader Cabrera-Bello followed with a 70.
Bjorn, trying to repeat his 2001 victory, is down in a tie for ninth, but still has only three strokes to make up.
England's Robert Rock, who managed to upstage Tiger Woods in Abu Dhabi in January, is still in contention at seven under par after carding a 69.
