DUBAI, 31 Jan, 2015 (AFP) - McIlroy took apart the front nine of the Majlis course with five birdies in his first eight holes, but could add just one more to the tally in his last 10 holes.
The back nine of the Majlis course, with its three reachable par-5s, is considerably easier than the front.
And yet, what the world number one did very well was keep the bogeys out of his card for a second successive day.
A gutsy par save on the par-5 18th hole, where he had hit his second shot into the water but made an up-and-down from the drop zone, saw him close the day with a six-under par 66.
His three-day total now stands at 20-under par 196, four better than 26-year-old Dane Morten Orum Madsen, who shot a similar bogey-free 66 in the third round.
Lee Westwood, who did not make a single bogey in his first 44 holes of the tournament, doubled the par-4 ninth from the middle of the fairway and a third-round 69 was good only for a third place at 14-under par 202, six shots behind the leader.
Scotland’s world number 34 and the defending champion, Stephen Gallacher will have his task cut out if he wants to join a select club of five players who have won the same tournament three successive times.
A mid-round wobble saw him make three bogeys over a stretch of five holes, and even though he recovered to shoot a two-under par 70, he is seven shots adrift of McIlroy.
Gallacher was tied alongside the English duo of Andy Sullivan, winner of South African Open earlier this year, and Race to Dubai leader Danny Willett, as well as Austria’s in-form Bernd Wiesberger.
After a two-feet putt for birdie lipped out on the par-5 10th hole, McIlroy was clearly frustrated out there on the golf course as his efforts to increase the lead did not fructify.
However, he said the conditions on the back nine had become tougher.
"I didn't put a foot wrong on the front nine and when I missed that little short putt on ten, it seemed like that momentum I had, just sort of went away and I had to scramble a little bit for pars coming in,” McIlroy said.
"The greens got firm and the wind got up a little bit so it was hard to get the ball close to the hole.
"You had to hit really quality shots to give yourself chances for birdies, and I didn't quite do that on the back nine like I did on the front.”
- Bogey-free again -McIlroy said it was important for him to make the par on the 18th.
"It meant a lot. To be bogey‑free again today was important to me, especially when you’re going out with the lead, not to make any mistakes makes it that much harder for anyone else.
"Just to get that up‑and‑down on the last was big for momentum going into tomorrow,” he added.
"I’ve been in this position many times before, so I know the pitfalls that are waiting out there. It's just a matter of sticking to the same game plan, being aggressive, making committed swings and giving myself as many chances for birdies as I can.”
Madsen, who followed up his nine-under par 63 on Friday with a 66, was mindful of the fact that he was going to be up against the world number one.
"Obviously, he’s going to be tough to beat. He looks like he’s playing pretty solidly out there, as well,” said the Danish world number 194.
"I’m just going to go out tomorrow and see if I can play some of the same golf that I played today. I won’t be too disappointed if I don’t win tomorrow.
"I’ll be happy if I do what I set out to do and play pretty solidly.”
Scores on Saturday in the third round of the Dubai Desert Classic:
196 - Rory McIlroy (NIR) 66-64-66
200 - Morten Madsen (DEN) 71-63-66
202 - Lee Westwood (ENG) 65-68-69
203 - Andy Sullivan (ENG) 65-68-70, Danny Willett (ENG) 67-66-70, Bernd Wiesberger (AUT) 64-69-70, Stephen Gallacher (SCO) 66-67-70
204 - Marc Warren (SCO) 66-65-73, Graeme McDowell (NIR) 67-65-72, Robert Rock (ENG) 68-67-69, Peter Uihlein (USA) 65-69-70, Alexander Norén (SWE) 68-67-69, Emiliano Grillo (ARG) 67-68-69, Pablo Larrazábal (ESP) 69-66-69, Renato Paratore (ITA) 68-66-70
205 - Gary Stal (FRA) 69-69-67, Thomas Aiken (RSA) 68-71-66, Seve Benson (ENG) 66-66-73
206 - An Byeong-Hun (KOR) 70-70-66, Henrik Stenson (SWE) 70-66-70, Nicolas Colsaerts (BEL) 65-74-67, Paul Lawrie (SCO) 69-71-66
207 - Maximilian Kieffer (GER) 66-68-73, Magnus Carlsson (SWE) 71-71-65, David Lipsky (USA) 68-71-68
208 - Paul Waring (ENG) 69-67-72, Thongchai Jaidee (THA) 71-68-69, Kristoffer Broberg (SWE) 69-69-70, Dawie Van der Walt (RSA) 69-73-66, Joost Luiten (NED) 68-70-70, Wade Ormsby (AUS) 69-69-70, Richard Green (AUS) 70-68-70, Jordi García Pinto (ESP) 70-66-72
209 - Anders Hansen (DEN) 66-72-71, Martin Kaymer (GER) 67-69-73, Grégory Bourdy (FRA) 69-71-69, Raphaël Jacquelin (FRA) 71-71-67, Grégory Havret (FRA) 68-71-70, Hennie Otto (RSA) 66-73-70, David Howell (ENG) 71-69-69, Mark Foster (ENG) 73-69-67
210 - Ross Fisher (ENG) 71-68-71, Edouard Espana (FRA) 70-70-70, Alexander Levy (FRA) 72-68-70, Alejandro Cañizares (ESP) 72-69-69, Bradley Dredge (WAL) 71-71-68
211 - Felipe Aguilar (CHI) 70-71-70, Michaël Lorenzo-Vera (FRA) 70-70-71, Anthony Wall (ENG) 69-70-72, Tom Lewis (ENG) 68-73-70, Andrew Johnston (ENG) 68-72-71, Garth Mulroy (RSA) 69-70-72, Yang Y.E. (KOR) 67-73-71
212 - Richard Bland (ENG) 71-69-72, Tyrrell Hatton (ENG) 71-69-72, Mikko Ilonen (FIN) 67-71-74, Álvaro Quirós (ESP) 73-69-70, Jorge Campillo (ESP) 67-70-75, Scott Jamieson (SCO) 74-68-70
213 - Oliver Farr (WAL) 73-68-72, Michael Hoey (NIR) 72-70-71, Thomas Pieters (BEL) 69-69-75, Moritz Lampert (GER) 71-67-75, Daniel Brooks (ENG) 69-73-71, Tommy Fleetwood (ENG) 72-70-71, Branden Grace (RSA) 73-69-71
214 - Ernie Els (RSA) 72-70-72, Jason Palmer (ENG) 74-68-72, Dominic Foos (GER) 71-71-72
215 - Edoardo Molinari (ITA) 70-72-73, Damien McGrane (IRL) 71-70-74, Peter Lawrie (IRL) 73-69-73, Matthew Baldwin (ENG) 71-71-73, Chris Doak (SCO) 72-70-73
216 - Richie Ramsay (SCO) 71-70-75