They are both 17 under par after third round 66s at the DP World Tour Championship and Donald has yet to drop a shot in the tournament. Jesper Parnevik in 1995 was the last to do that in winning an event on the circuit.
Everybody else looks too far back given the pedigree of the leaders. Donald has now played 100 holes in the event without a bogey.
"I'm not sure I can believe that," he said on being told of the fact. "That's pretty good. I guess that's my style - I don't make too many mistakes."
Donald played the front nine much the better, a four-birdie 32 compared to McIlroy's 35 which contained an opening bogey after he drove into a bunker, but then birdies at the third and sixth. It was on the inward half that the 23-year-old has really prospered all week, though, and after picking up more shots on the 11th and 12th he found the green in two at the long 14th and holed an eagle putt of around 30 feet.
Donald had needed to sink a 10-footer just for birdie there after twice finding the left-hand rough and he added another at the par five last after pitching to six feet before McIlroy, in rough off the tee, matched it with a putt of similar distance.
Scot Marc Warren, joint halfway leader with Donald and McIlroy, managed only a 72 to remain 11 under, his troubles starting when he pulled his drive down the long second into bushes, took a penalty drop and ran up a bogey six.
McIlroy achieved his score despite another rough night with a fever.
"I woke up at four and was not feeling great, but I guess the adrenaline keeps you going when playing," he said. Told about Donald's run of without a bogey he smiled and replied: "He must be due one."