Abu Dhabi, United Arab Emirates (SportsNetwork.com) - Martin Kaymer posted a bogey-free, 5-under 67 on Friday and remained one stroke clear of the field after two rounds of the Abu Dhabi HSBC Golf Championship.

Kaymer ended 36 holes at 13-under-par 131, matching his own 36-hole scoring record at this event. Kaymer first posted a 131 total in 2008, when he went on to the first of his three victories at this tournament.

Thomas Pieters matched Kaymer's 67 to remain one stroke off the pace at minus-12 on the National Course at Abu Dhabi Golf Club.

World No. 1 Rory McIlroy aced the par-3 15th and that propelled him to a 6- under 66. The three-time runner-up is alone in third place at 11-under 133.

McIlroy birdied the first and second. After three pars in a row, he faltered to a bogey at the sixth and closed the front nine with three more pars.

Like the front nine, McIlroy birdied the first two holes of the back. The highlight of his round came at the par-3 15th. His tee shot landed just left of the hole, bounced right, then rolled into the hole.

"It definitely made up for the two previous holes. It was a perfect number, it was straight downwind, 177 yards, and I had a 9-iron," McIlroy said of his first professional hole-in-one. "I had a similar shot on No. 12 and I hit 9- iron there and it pitched at 174 yards, so I knew it was a pretty good number. As soon as it left the (club), I knew it had a chance."

McIlroy rolled in a 15-footer for birdie at the last to end two behind Kaymer.

"I felt really good. I went to the range yesterday and worked on a couple things, and I drove the ball much better today, which you need to around here," said McIlroy. "I played really well from tee to green. I felt like I was hitting some good putts as well, but they just weren't dropping. I'm not going to complain with a 66."

Kaymer started on the back nine Friday and parred his first two holes. He dropped in back-to-back birdies at 12 and 13 to move to 10-under.

The German parred his next four holes before making birdie at the 18th, then followed with another birdie at the first, where he holed out from a greenside bunker.

Kaymer ran off six straight pars from the second and birdied the par-5 eighth for the second straight day to get to 13-under. He parred the ninth, his last, to end there.

"I didn't miss many fairways, which gives you the opportunity to go for a lot of flags. And to be honest, I really believe the golf course plays two or three shots tougher in the morning than in the afternoon because once you miss the fairway, you're in that thick, wet grass and then it's almost impossible to get home in two on the par-4s," Kaymer stated.

Pieters followed three pars to open his round with his second birdie in two days at the 13th. He came back with birdies at 15 and 17 to put him at 10- under heading to the front nine.

Around the turn, Pieters got going with birdies at the first and third. A birdie at the sixth moved him into a share of the lead with Kaymer at minus-13. However, Pieters' tee shot at the par-4 ninth bounced into the water right of the fairway, leading to a closing bogey that dropped him one behind Kaymer.

James Morrison also carded a 67 and Peter Uihlein joined him in fourth place at minus-9 with a 4-under 68. Alexander Levy (70) and Richard Green (68) are one stroke further back at 8-under-par 136.

NOTES: Kaymer has a piece of the 36-hole lead for the eighth time on the European Tour. He has won four of the previous seven times he was in this position, including his 2008 and 2011 titles at this event ... Seventy-two players made the cut at 2-under-par 142 with 2013 runner-up Justin Rose, Ernie Els and Rickie Fowler all making it on the number ... Among those that missed the cut were last year's winner Pablo Larrazabal, Darren Clarke, Henrik Stenson, Edoardo Molinari, Matteo Manassero and Chris DiMarco.