It was wet and it was windy at Wentworth. In fact, for much of the second round proceedings, it was pretty rotten. This was a day for rolling up the sleeves, gritting the teeth and getting on with it. Yes, the golf writers really are a hardy, spirited bunch.
Out on the West Course, it was worse but McIlroy, not a player exactly renowned for showing such fighting qualities in inclement conditions, demonstrated a professional maturity and a willingness to grind it out and a battling one-under 71 for a five-under 139 left him tucked in among the frontrunners at the halfway stage of the European Tour's flagship event.
Thomas Bjorn, who raced to the top with an opening 62, added a 72 yesterday and was joined in a share of the lead on a 10-under 134 by Shane Lowry, but McIlroy is very much in the mix. With a combination of the miserable conditions and the well-documented personal troubles that continue to hang over him like a vast, damp cloot, the Northern Irishman probably wished he was anywhere but here.
A brace of bogeys at the second and third certainly didn't help the hang-dog look and when he adopted that favoured approach of the club hacker by knifing a bunker shot through the back of the seventh green, the ensuing double-bogey 6 led to the kind of crumpled, despondent body language that made a sack of tatties look buoyant.
Credit where credit is due, though. McIlroy's subsequent salvage operation was impressive and the catalyst for his robust recovery was provided by an eagle-3 on the 12th. Despite a further leaked shot on the 13th, the two-time major champion finished with a flourish and picked up birdies on three of his last four holes to repair some of the earlier damage.
With 36 holes to play, McIlroy is still in the hunt. Given the current state of his mangled mind, and the fact that he had missed the cut at Wentworth in his last two appearances here, McIlroy's presence in the upper echelons is worthy of admiration.
"Hopefully I can make a run at it," said the 25-year-old. "I have exceeded my expectations so far. I don't know about exceeding them wildly, but reasonably at least.
"I think once you get inside the ropes, you are concentrating on your golf. It's almost like it's a nice four or five hours of a release in some way just to get everything out of your head apart from doing the job at hand. You can't let your mind wander at all when you're trying to win a golf tournament. It's the hours in the day when you're away from the golf that are probably a little more difficult."
Bjorn was certainly impressed by McIlroy's resolve. "He is determined to show the world that he is still a good player in the circumstances and the golfing world is a better place when Rory McIlroy is playing well," said the Danish co-leader. "Tough things happen on the road of life and we all have to deal with them. If anyone can do it, he can."
It was a testing day for Bjorn, too. In comparison to day one, when he raced round the West Course like a nippy BMW on the open road, yesterday's slog must have felt like sitting in rush hour on the M25.
"It was just impossible to find a good rhythm and Retief [Goosen] left us with injury after five holes, so we got caught in a two ball," said Bjorn, who holed a raking bunker shot on the 15th for a 3 as he birdied two of his last four holes to haul himself back to level-par with a late rally.
"It just seemed like all day we were waiting and waiting for a long time on a lot of shots."
Lowry, a former Irish amateur team-mate of McIlroy, refuses to go away and successive birdies at 17 and 18, the last coming by virtue of a putt from almost 20 feet, gave him a 70 and a share of the lead.
Luke Donald was the most upwardly mobile of the chasing pack as he bolstered his assault for a third PGA crown with an eventful 67 for which left him four off the pace in a tie for third on a six-under 138. The middle part of his round was certainly a case of three and easy. From the eighth he reeled off five successive threes - birdie, birdie, par, birdie, eagle - before putting the tin lid on a purposeful round with a putt of 40 feet for another gain on the par-5 18th.
"I always try to let my short game do the scoring for me and that was the key today," reflected Donald, who won back-to-back PGA titles in 2011 and 2012 and is now right in the thick of it again on this happy hunting ground.
The man who succeeded Donald as champion last year, Matteo Manassero, did not enjoy his return to the scene of his greatest triumph, however. The 21-year-old, who became the event's youngest-ever champion 12 months ago, posted a 71 but his crippling 80 in round one had left him with too much of a mountain to climb and he joined the early casualty list.