Today's last round of the European Tour season will see the world's top two going head-to-head in the final group of the DP World Tour Championship in Dubai.
At 17 under par, both are three clear of South Africans Charl Schwartzel and Louis Oosthuizen after third-round 66s, while the gritty challenge of Scotland's Marc Warren – a joint leader after the second round – melted away in the desert sun to leave him on 11 under following a 72.
Donald is trying to become the first player to win an event on the circuit without dropping a stroke since Jesper Parnevik at the 1995 Scandinavian Masters.
"He must be due a bogey," said McIlroy, who was up at 4am after another rough night with a fever brought on, he believes, by sunstroke.
"Thanks for putting a curse on it," Donald said when told he was also on a run of 100 holes without a bogey on the Greg Norman-designed course.
They are both looking forward, though, to what promises to be a mouth-watering "Duel in the Sun". McIlroy, having already emulated Donald's double last year of topping the money lists on both sides of the Atlantic, is going for a fifth victory of 2012 – a triumph that would be worth £1.46 million.
Donald, back to second on the world rankings after his win in Japan last Sunday, is trying for a fourth victory of 2012, one that could earn him almost £1.25 million if he climbs from eighth to second on the Order of Merit. McIlroy, pumped full of painkillers, was the happier of the two to be on level terms at the end of the third day just as they were at the start of battle.
He said: "At one stage he was three or four ahead. I wanted to keep it close, but to play like I did on the back nine was great and it's going to be a very exciting day. I want to win badly, though. I want to finish the year off well."
Donald was impressed by his run without dropping a stroke, but not surprised by it. "I don't make too many mistakes," he said. Joint halfway leader at the start with Warren, the Englishman grabbed birdies at the second, third, seventh and ninth.
It has been on the inward half that the 23-year-old McIlroy has prospered all week, though, and after turning in 35 he birdied the 11th and 12th and holed an eagle putt of around 30 feet at the long 14th.
Both then put more distance between themselves and the field at the par-5 last, both pitching to inside seven feet to set up further birdies.
Warren is now in a tie for seventh. Schwartzel and Oosthuizen went past him by scoring 67 and 68 respectively, while fifth-placed pair Joost Luiten and Branden Grace shot 67 and 70.
But most fans will have eyes only for the final pair when play resumes. "I know my game is different to Rory's," said Donald. "He's a power player and obviously he's got a great short game as well.
"I can't go out and try to hit the ball harder or anything like that. I just have to play my own game and not get ahead of myself."
Richie Ramsay shot a 73 to be on 208, with Scott Jamieson one shot behind after a 72. Stephen Gallacher was another shot back, also after a 72.