Kaymer hit five birdies to take control in Abu Dhabi
-12 M Kaymer (Ger) -9 C Schwartzel (SA)-8 G McDowell (NI) -7 R Echenique (Arg), N Fasth (Swe), D Lynn (Eng)
Selected others: -6 R McIlroy (NI) -5 C Montgomerie (Sco) -3 P Mickelson (US) -2 MA Jimenez (Spa), -1 P Casey (Eng)
Extended second-round leaderboard
Martin Kaymer's brilliant round of 65 has kept him on course to retain the Abu Dhabi Championship and usurp Tiger Woods as the world number two.
Kaymer seized control of the event from South African Charl Schwartzel with five birdies in his first seven holes.
But the disqualification of Irishman Padraig Harrington when lying in second place was the talking point of the day.
"The way he was playing I think he would have had a chance to win," said Kaymer. "He is a little unlucky there."
Harrington, 39, was disqualified after his hand brushed the back of his ball as he replaced it in front of his marker, an incident that came to light only after he had
signed for a first-round 65
Five birdies in total saw Kaymer, who is seeking his third win in Abu Dhabi in four years, move to 12 under par at the halfway stage of the tournament, three shots ahead of Schwartzel.
World number one Lee Westwood dropped three late shots but, despite a 75, survived the cut with nothing to spare at level par.
Open champion Louis Oosthuizen and Ian Poulter missed by one, Darren Clarke by two and new Ryder Cup captain Jose Maria Olazabal by four.