The 25-year-old, who has struggled to follow up on good first rounds this season, exorcised his demons in style with seven birdies and one bogey at Royal Liverpool on Friday.
It leaves him four shots clear of American Dustin Johnson at -12 and out in front at the halfway point for the first time in a major since 2011, when he went on to clinch the US Open.
McIlroy could have been forgiven for fearing the worst as he began his second round with a bogey after overshooting the green, but he soon followed up with birdies on the fifth and sixth holes.
The Holywood man picked up further shots on the eighth and tenth before surprisingly missing from four feet on the 11th - he went on to hole from that distance on the 15th after a superb tee shot.
McIlroy finished his round in style with two consecutive birdies to leave him well in contention for a third major title and first Open win this weekend.
In contrast, Tiger Woods carded a birdie on the final hole to ensure he made the cut with a round of 77 which left him 14 shots adrift of the Northern Irishman.
Meanwhile Graeme McDowell was on three under after a round which included six birdies and three bogeys, and Darren Clark finished on par.
Ballymoney man Michael Hoey was forced to withdraw from the tournament after seven holes of his second round with a foot injury.