McIlroy added a second round two-under-par 70 to his opening score of 67 to move within a shot of the leading duo of Willett and Scotland's Marc Warren on the Palmer Course at the K. Club.
Willett has bounced back from missing the cut in last week's Players Championship, adding a 71 to his opening score of 65 as the Englishman seeks to win for a third occasion this season.
Warren's score is his lowest in some six months and the first occasion in 10 events this year, including six where he has missed the halfway but, where the 35-year old will have strung together back-to-back four round showings.
Willett had moved to nine under par with back-to-back birdies at his 13th and 14th holes but then dropped the fourth shot of his round at his 16th to fall back into a tie with Warren who had finished his round ahead of the Augusta National champion.
“A 71 is not too bad as it was pretty steady, but then scrappy at times,” said Willett.
“The golf course is tricky, as there is a lot of crosswinds while the rough is a little bit juicy so the key is hitting fairways, and if you don't, you find yourself out of position and you're going to have to get up-and-down for par.
“I did drop a couple of silly shots out there, but eight under par is not too bad, I'm tied for the lead and in a good position heading into the weekend.”
In contrast, Warren has not been in position for victory since capturing the 2014 Made in Denmark title, and his fourth Tour title.
However, the Scot is not about to be overawed given he and Willett will be partnered over the third round in the Euro 4m event.
“I am very pleased with a 66 given the golf course is tough, and the conditions today moreso,” he said.
“I would have taken anything roundabout the 70 mark this morning but then the greens were absolutely pure this morning, so delighted to take advantage of that.”
McIlroy is confident he's finally turned around an indifferent season as he seeks a first success since last November in capturing the European Tour season-ending DP World Tour Championship in Dubai.
The current World No. 3 grabbed five birdies in his round of 70 and none better than holing a 30-footer at his last.
However, McIlroy also posted three bogeys, something he says he needs to eradicate if he's to win for a first time as a professional in Ireland.
“There was still a little bit of frustration out there as I felt I could have been better today,” he said.
“But if you look at the leader board I'm only one shot off the lead. I have a couple of rounds under par but then it would have been nice to shoot something in the 60s but I felt I controlled my game pretty well.
“I made a few more mistakes today, and it was pretty tricky with the wins but then a 70 is as decent score.
“And with my tournament host cap on, it's great to see Danny up there. I was very pleased that he committed to come and play.
“Anytime you have a current Major Champion up there near the top of the leader board, always makes for a better tournament.”
The leading trio were three shots clear of the the South African pair of Richard Sterne (68) and Jaco Van Zyl (72) who shared fourth place on four under par. – AFP
Original source: McIlroy has his work cut out