Rory McIlroy started his US PGA Championship bid with focus on building a first-round platform for future success – then ended Thursday aware of the need to instead break down driving data and address past pain.

A smiling McIlroy arrived this week at Aronimink celebrating the “perks” of life as a back-to-back Masters champion and member of golf’s grand slam club thanks to that clean sweep of majors.

But the smile disappeared on Thursday night as he offered a grim one-word expletive of “s**t” to sum up a 74 that left him four-over-par and outside the projected cut line before launching a second round on Friday (7.05pm, UK start) with the 37-year-old highlighting “a problem all year for the most part”.

With pre-tournament talk around McIlroy’s bid to win the season’s second major and long-term goals bolstered by retaining the Augusta green jacket and an appearance at his beloved Quail Hollow course for last week’s Truist Championship, the post-round chat centred instead on a pressing fight not only for survival heading into the weekend but the demand to address the potential long-term damage caused by ongoing driver concerns.

placeholder image — Rory McIlroy has been left to address driver concerns following early US PGA Championship frustrations. (Photo by Emilee Chinn/Getty Images)

Having spent time on the practice range across the penultimate night of his Masters triumph last month to stop that rot, McIlroy was back on Thursday night putting in the behind-the-scenes hard yards to review and re-evaluate following a return of troubles off the tee.

His Masters adventure thrilled fans with a six-shot lead setting a record after 36 holes before Saturday pain led to McIlroy putting himself through the practice paces with help from caddie Harry Diamond to discover answers.

Thursday’s first round presented more questions.

With McIlroy, magic can always follow the misery and fans retain faith in his fightback from almost any position. But he was left to reflect on hard data this week exposing a fundamental flaw in a traditional strength which put not only his present ambitions in the US PGA Championship at risk but, significantly, presented concerns over an impact on continued rewards.

Four successive bogeys to wrap up Thursday at Aronimink left McIlroy looking at some damning numbers beyond the scorecard.

Although he remains the statistical PGA Tour leader in Strokes Gained: Off the Tee across this season, his Masters practice, admitted subsequent work between majors and Thursday’s frustrations identify an area offering greater potential pain than the blister which claimed so much of the build-up spotlight.

Hitting just five fairways across that initial round, McIlroy discussed his frustration at a course which tested the full field and returned low scoring as it claimed a higher-than-expected number of victims.

“I started missing fairways...I missed the fairway right on 4, the fairway right on 6, the fairway right on 7, fairway right on 9,” he said on Thursday following a score shared by Tom McKibbin, another Northern Ireland player. “From there, it's hard...I didn't have great angles either. Then obviously you start missing it just off the edges of these greens, it gets tricky. I made that birdie on 5 to get back to even-par after the soft bogey on 4, then I just got on that bogey train at the end.

"I'm just not driving the ball well enough...it's been a problem all year for the most part. I miss it right and then I want to try to correct it and then I'll overdo it and I'll miss it left. It's a little bit of back and forth that way...so that's pretty frustrating, especially when I pride myself on driving the ball well.

"I just need to try to figure it out...I honestly thought I'd figured it out. Coming in here, I hit it well on Sunday at Quail Hollow and then hit it good at home on Monday then obviously I had to curtail the practice round Tuesday (with a foot blister) but hit it decent yesterday. Once I get under the gun, it just seems like it starts to go a little bit wayward on me.”

He added on the course’s particular challenges: “If the pin's on the left, you miss it right, it's fine. But I got a couple of lies today that were particularly bad...the one on the 10th hole starting off, that's as bad as I've seen. There is certainly a penalty for missing the fairway...probably more than what I anticipated after being here two Fridays ago.

“I think it's the breezy conditions that are sort of making the scoring what it is…say you have a pin tucked over on the left side of the green and the wind's coming off the left, it's hard to get it over there. Seeing a lot of guys hit it to 20 and 30 feet...they're good shots, it's just hard to make a lot of those putts.”