Rory McIlroy incurred a two-shot penalty during the second round of the Abu Dhabi Championship as he fell from joint leader to joint third.
Northern Ireland's US Open champion brushed sand away from his line on the ninth hole, the penalty arising from the fact his ball was not on the green.
His level-par round of 72, which left him on five under, featured two double bogeys, two bogeys and six birdies.
McIlroy is tied with Tiger Woods, two shots behind leader Thorbjorn Olesen.
Northern Ireland's Gareth Maybin (70) and Italy's Matteo Manassero (65) trail Denmark's Olesen (67) by one.
McIlroy would have joined fellow 22-year-old Olesen on top of the leaderboard but for his misdemeanour on the par-four ninth.
Just off the green in two, playing partner and world number one Luke Donald pointed out his mistake and a referee was called.
McIlroy conceded he was guilty of a lack of concentration and being unsure of the rule.
"Luke said 'I don't think you can do that'," he said. "And then I was like 'Oh yeah I can't, can I?' It twigged on me straightaway.
"It undid all the great work I'd done after the bad start."
Woods is also in contention after rolling in five birdie putts in a second round that contained two bogeys, his first dropped shots of the tournament.
"I played well," said the 14-time major winner. "A lot of things are starting to feel very comfortable but it's tough out there, the rough is getting deeper and more lush."
World number two Lee Westwood, who is battling a neck injury, was in danger of missing the cut after three bogeys in his opening five holes.
However, the Englishman, who started on the 10th, traded two birdies with two more dropped shots around the turn.
But three successive birdies from the fifth lifted him to a 72 and level par for the tournament.
"I've had it for about a month, but this is the first time I've played three days in a row," he said.
"The pain goes down into my elbow and it feels like somebody is driving a needle in there."
When asked if there was any possibility of him withdrawing from the tournament, he added: "If I'd hit it in the long rough I might have had to think about it, but hopefully I'll be OK."
Donald will also be around for the weekend after he also shot a 72, finishing on one under par.
However, three-time winner and defending champion Martin Kaymer is out after following his opening-round 77 with a 73 to finish six over.