Rory McIlroy was three under after five holes but stumbled to a 76 on day one of the BMW PGA Championship at Wentworth, so why did his day go so wrong after such a bright start? Ewen Murray offers an explanation …

It was such a shame to see a disconsolate Rory McIlroy walk wearily off the 18th green to sign for a four-over 76 at Wentworth, particularly as everything looked in good order early on. Eagle at four, birdie at five, had a good chance at six, and he almost holed his approach to the seventh.

But he missed from four feet, and that was the first of many errors as his day went horribly wrong.

McIlroy has just been voted PGA Tour Player of the Year and has achieved so much in the game, and I think he’s still capable of achieving much, much more. But, like all of the top professionals, without exception, there are minor flaws that creep into a game that can be tough to iron out during a round.

Let’s go back to 2011 when he led the Masters by four after 54 holes, pummelled his opening drive on Sunday further than anyone, but his wedge missed the target by some distance. I don’t think he’s ever fully corrected that problem with the short-irons. In his mind, he’s seeing a left-to-right ball flight, but his swing is generally favouring the right-to-left.

The 17th shouldn’t have been a problem for him with his natural shape of shot, but he’s aimed left, it stayed left and disappeared out of bounds. And then, almost inevitably, he’s over-corrected at the last and blocked three in a row to the right.

I said in commentary that he’s had a day where he felt underneath with his swing. Feeling on top promotes a fade, being underneath leads to a draw. It just seems that he’s stuck between hitting his natural shot and the one he sees in his mind.

It’s an easy thing to do on the range, but not when you’re out there playing a competitive round of golf on the big stage, even for someone with such an immense talent as Rory.

He’s had a few bad days over the West Course. In 28 rounds, he’s had a dozen of 73 or more and nine have gone over 74, so is it more of a mental issue for him than technical?

Being three under after five holes suggests otherwise, and at that time he’d have been thinking ahead to a positive day rather than dwelling on the negatives of the past. Rory just had one of those days where the wheels came off when he took five at the eighth despite having wedge in hand for his second, and he struggled to put them back on thereafter.

Even with all his great results this year, three big wins and several top-10s worldwide, I still think he gets into a habit of swinging on a lower plane which takes him inside the line. You can deal with that with the longer clubs, but you don’t have the time to adjust with the short-irons.

Then, mistakes are magnified further in the long game, and we saw evidence of that on the 17th and 18th tees today. With the conflict between swing in mind, he’s often at the mercy of the speed of his hands. It just needs a slight technical change to correct that, and he’ll be working hard on the range with coach, Michael Bannon.

What we saw from him over his last 11 holes today was similar to his first round at Royal Portrush in July, when you get into such a rut that is tough to stop the bleeding. Mistakes are compounded by further mistakes, and he’s left himself a tough task to make the cut once again.

He will need a 68 at least on Friday to be around for the weekend but, as we saw at The Open, he’s more than capable of following up a bad round with something extra special.

(c) Sky Sports 2019: BMW PGA: Rory McIlroy problems technical, not mental, says Ewen Murray