McIlroy rallies in tough conditions
With a swirling wind and intermittent rain making conditions difficult for the early starters, McIlroy covered the front nine of his second round at Wentworth in three over par.
That left McIlroy one under for the tournament with the halfway cut projected at that point to fall at level par, but just as he did in the recent Players Championship at Sawgrass, McIlroy rallied strongly on the back nine.
An eagle on the 12th for the second day running was followed by a bogey on the 13th, but birdies on the 15th, 16th and 18th gave McIlroy a 71 and halfway total of five under par.
And with overnight leader Thomas Bjorn starting his round with a bogey on the first, that was within four shots of the lead.
"I did not start off particularly well and made a mess of the seventh, but came back well and hit some quality shots on the back nine," said McIlroy, who thinned a bunker shot on the seventh to run up a double-bogey six on a hole he eagled on Thursday.
"Anything under par this morning was a decent score and to birdie three of the last four holes is pretty pleasing."
McIlroy announced on Wednesday that he had called off his planned November wedding to former world number one tennis player Caroline Wozniacki, even though the invitations had just been sent out.
The 25-year-old admitted he would therefore find it very difficult to concentrate on his golf in the European Tour's flagship event, but managed an opening 68 and felt slightly better on Friday.
"I was apprehensive going out yesterday, I honestly didn't know what to expect and it was good I had the quick turnaround to get back on the golf course," he added.
"I have exceeded my expectations so far. Once you get inside the ropes you are concentrating on your golf and it's almost a nice four or five-hour release to concentrate on the job at hand."
Spain's Rafael Cabrera-Bello had set the clubhouse target on six under after a round of 73, with Sweden's Jonas Blixt - joint second in the Masters last month - alongside McIlroy on five under following a 71.