What could have been possible for the 35-year-old from Holywood in a season in which he achieved three victories, but – quite honestly – not in the tournaments in which he most wanted to triumph.

There are failures and there are failures, some worse than others, and the fact that McIlroy is so consistent in his success is a mark of his tireless excellence.

This latest disappointment at the hands of American Billy Horschel should be easier for him to cope with than some of the other disappointments he has suffered this year.

McIlroy shot 67 in the final group to finish 20 under par, but was not at his best. He remained tenacious and tactical and unleashed his brilliant performance to give himself a chance at victory.

His dominant approach shot to the green of the par 5 17th hole was followed by a sensational 46-foot putt, which earned him only his second eagle of the last day on this penultimate hole.

Suddenly McIlroy was able to win with a birdie at the end and was standing in the middle of the final fairway. It was a long approach shot, the tournament was at stake, thousands upon thousands were watching – a truly magnificent finish.

How much easier would this very difficult shot have been if he had been the reigning US Open champion, Irish Open winner or Olympic medalist?

Who knows? If only, if only, should have.

But one suspects that in this alternate universe, the enormous pressure of this moment might have been a little easier to handle. In reality, he seemed nervous, tormented, and not enjoying the moment.

Of course, appearances can be deceiving, but the resulting 4-iron was too short and went left, luckily it didn’t land in the water. He could only make par.

McIlroy seemed more relaxed in the play-off and managed two excellent birdies. But Horschel, who also finished with a 67, finally holed out from around 9 meters and scored an eagle that gave him the win.

The better man of the day won and once again it took a brilliant performance to stop McIlroy, as had happened to Hojgaard seven days earlier and to Bryson DeChambeau at the US Open in Pinehurst in June.

“It’s inevitable that you’re going to have disappointments,” McIlroy argued. “Unfortunately, I’m getting too used to what it’s like to have disappointments and hopefully things will turn around.”

Looking at his performances on the DP World Tour this year, McIlroy has never finished worse than the top four in five events, including his win at the Dubai Desert Classic in January.

Overall, only six players have had better results than him in these tournaments. He has hit a total of 604. His batting average of 68.71 compares very favorably with the average of 70.95.

The current third-ranked player in the world is a class ahead of almost everyone else on the European tour. In November he will win his sixth title at the Race to Dubai.

Colin Montgomerie’s record haul of eight Orders of Merit is under serious threat from the undisputed king of European golf of this generation.

“I think I really have a knack for playing good enough golf,” McIlroy said as the Wentworth crowd headed for the exit. “Even when I don’t feel like I’m playing my best, I play good enough golf to always have a chance.”

He has every right to think that way. “When I go to a golf tournament, I know that the others have to beat me to have a chance of winning,” he said.

“That’s how it feels. So that’s a pretty good position.”

McIlroy was at his best when he won at Quail Hollow on the PGA Tour the week before the US PGA Championship in May. He was unable to maintain that form at Valhalla and then came a devastating end at Pinehurst the following month.

With a two-shot lead and brilliant play, he seemed destined to end a ten-year wait for his fifth major title at the US Open, but he dropped three shots in the final four holes, including a tiny putt on the 16th.

It was miserable, and made worse by the fact that a weary DeChambeau miraculously escaped a bunker and made the winning par on the final hole, an outcome that might have been the end for a lesser golfer.

Yes, McIlroy hasn’t won since then and has failed to capitalize on opportunities. Some of those misses may have left scars – he missed a few shots on the home stretch in Northern Ireland just over a week ago – but this loss to Wentworth was different.

In fact, his performance there showed that he can put bitter disappointments behind him and move on. He is a golf Chumbawamba, ready to be knocked down but get back up again.

There are good reasons for the “drumming on the barrel”, because that is one of its many qualities.

“I’m a better golfer than I was five years ago,” McIlroy concluded. “I know that. It’s just about turning these close calls into wins.”