The Northern Irishman is now alongside Ryder Cup teammate Tyrrell Hatton on five under par as he closes in on a record-equalling eighth Race to Dubai title.
McIlroy made a strong start on the Earth Course at Jumeirah Golf Estates, picking up three birdies in his opening eight holes before adding another at the tenth.
However, windy conditions made scoring increasingly difficult, with bogeys at the 12th, 16th and 17th threatening to derail his round.
A birdie at the final hole ensured McIlroy finished level with Hatton, who had set the clubhouse target earlier in the day.
Race to Dubai leader Eugenio Chacarra is currently tied for 11th after the opening two rounds, leaving McIlroy in a strong position to claim his fifth consecutive title.
"I played very solidly for those first 11 holes," McIlroy said.
"And then 12 felt like the first time I'd really put myself out of position. And once you do start putting yourself out of position on this golf course, this setup, these conditions, it starts to get very, very difficult.
"It's very easy to make bogeys out there. It's very, very tricky once you get yourself out of position. So, easy to make bogeys, but it was nice to at least birdie the last and feel like I sort of salvaged the day a little bit with that birdie.
"I've been coming to this golf course for 17 years, and this is the toughest I think it's ever played. So in my mind it's sort of like, well, you should be going out and shooting 66 or 65, and the course just isn't set up that way this week. And you just have to show a little bit more patience out there. And I started to get maybe a little bit frustrated with the course on the way in. But I think it's just the nature of it. It's a tough test."
McIlroy has won the DP World Tour Championship three times and could secure a fourth victory, along with the Harry Vardon Trophy, having finished runner-up in a play-off last year.
"I want to win this tournament," he added.
"You know, I've won four times down the road at Emirates. It'd be nice to win four times here. So, yeah, I want to win the tournament. And if I win the tournament, that's all I can do. It doesn't really matter what any of the other guys do, you know, if they play well enough. But if I go and I win the first trophy on Sunday, then the second trophy should take care of itself."
First round leader Joost Luiten is one shot behind the leading duo on four-under with Kristoffer Reitan, one ahead of the trio of Mikael Lindberg, Freddy Schott and Victor Perez.
Three-time tournament winner Jon Rahm is also well placed alongside compatriot David Puig and South African Jayden Schaper, while Chacarra is among a group of players at one-under and the Spaniard is hopeful he can give himself a chance over the weekend.