Defending champion Martin Kaymer extended his lead at the Abu Dhabi Golf Championship to five strokes over Rory McIlroy after shooting a 6-under 66 in the third round on Saturday.

Kaymer, the 2010 PGA Championship winner, birdied three of his last four holes to total 18-under 198 at the Abu Dhabi Golf Club.

"The great thing is I've made only one bogey so far, and that was the first day," Kaymer said. "I played very consistently. I've made a lot of birdies the last three days."

McIlroy finished birdie-eagle for a 65 to move into second place.

David Lynn of England (67) is at 204, two strokes ahead of Race to Dubai leader Charl Schwartzel of South Africa (71) and Alexander Noren of Sweden (67).

U.S. Open champion Graeme McDowell struggled with putting and finished with a 71. Paul Casey of England (67) made a hole-in-one at the 12th.

Four-time major winner Phil Mickelson was 3 under at the turn, only to make four bogeys on the back nine. He shot a 72 and trails the leader by 15 strokes. Top-ranked Lee Westwood had a 73 and is tied for 65th.

Kaymer beat McIlroy by two shots in last year's tournament, and the Northern Irishman is aware he faces a challenge on Sunday.

"Kaymer is very, very good on this golf course," McIlroy said. "He's always good when leading from the front as well, so I'm going to have a difficult time to try and catch him."