"I'm still leading the tournament, even though the day wasn't the best one," said Quiros, who won this year's Omega Dubai Desert Classic.
"I'm still hitting good shots and good putts, so this is the only thing that matters."
South African Louis Oosthuizen, like Lawrie a former Open Champion, is third a stroke further back after also handing in a 66.
Donald described his six-birdie, no bogey display as "the perfect round for me - exactly what I wanted."
He had started his first two rounds with a bogey, but this time it was with a 14 foot birdie putt and he added more on the second, fifth and eighth to turn in 32.
With no sight of McIlroy on the leaderboard by then, Donald picked up further shots at the 15th and 16th.
He is not taking anything for granted yet, though.
"You can't in this game. I would be foolish to think it's over," he said.
"Tomorrow it will be just like any other day in terms of my focus.
"It will be on trying to catch whoever is the leader and trying to win the tournament. I'm not going to count on anything.
"But if it all works out tomorrow night will be fun - it would be a pretty amazing feat. It's history."
McIlroy's girlfriend Caroline Wozniacki, the tennis world number one, turned up to watch on the back nine and saw the 22 year old come home in a four under 32 with birdies at the 11th, 12th, 16th and 18th.
But the damage came earlier. He drove into sand on the third, then ran up a double bogey seven at the long seventh after hooking into an unplayable lie in a bush with a five wood second and then leaving his chip short of the green.
"I'm tired. I'm very tired," he said.
"But I don't want to say that's the cause of playing the way I did on the front nine because I came back.
"I'm not 100 per cent, but that should not stop me. I was trying to stay patient and hit good shots, but I just couldn't do it.
"Luke has played well all year and I expect him to have another solid round. I don't think he's been given enough credit for the golf he's played, but from within the golfing family I am sure he will receive a lot of plaudits."
Quiros eagled the seventh from eight feet and had four birdies, but there were also four bogeys on his card.
His closest overnight challenger, Swede Peter Hanson, managed only a 71 and Lawrie seized the chance to be in the final group on the final day of the final event when he played the last six holes in five under.
The closing eagle followed birdies on the 13th, 14th and 16th.