Rory McIlroy plays his tee shot on the ninth hole during the final round at the 2013 U.S. Open at Merion Golf Club in Ardmore, Pa. on Sunday, June 16, 2013. (Copyright USGA/Joel Kowsky) Rory McIlroy shrugged off the club mangling incident that marred his US Open finale as nothing more than “a moment of frustration and silly thing to do.”

But whatever about his lack of genuine remorse over throwing one club and bending another out of shape in a fit of pique, he seems genuinely sorry that after putting 14 Nike clubs in the bag in January he only played four and half competitive rounds over the next six weeks.

The 24-year old’s $200m-plus club deal has brought him nothing but heartbreak so far this year and he admits that he made a major mistake in trying to be competitive against the best players in the world using equipment he clearly hadn’t worked hard enough to adjust to his game.

“It’s definitely a different feeling,” McIlroy said at Merion on Sunday.  “The thing about new equipment, you can stand on the range all you want and hit balls, but you really need to test it on the course.  

Rory McIlroy plays his tee shot on the 11th hole during the final round at the 2013 U.S. Open at Merion Golf Club in Ardmore, Pa. on Sunday, June 16, 2013. (Copyright USGA/Joel Kowsky) “The numbers could be great on the Trackman, but once you get out and test it in competitive play [it’s different].  

“And that’s something I didn’t do at the start of the year. I only played twice by the end of February, I think.

“So I sort of needed to play a little bit more. If I was to do it all over again, I would have done things slightly differently.”

In losing to Shane Lowry in the first round of the WGC-Accenture Match Play, McIlroy showed that his game was far from sharp and when he walked off the course “seeing red” after completing just 26 holes in the Honda Classic, the red light came on.

His form has been wildly erratic since then and while his good golf is still very good, his misses are proving extremely costly.

Without even beginning to analyse the distraction caused by his falling out with Horizon Sports Management and almost certain departure, he knows only hard work will put him back where he was at the end of last year.

Padraig Harrington lines up his putt on the first green during the third round at the 2013 U.S. Open at Merion Golf Club in Ardmore, Pa. on Saturday, June 15, 2013. (Copyright USGA/Darren Carroll) On his scheduling mistakes, he said: “You learn from that and it’s hopefully something I’ll never have to do in my career again. So I don’t mind taking three months to figure it out and go from there.”

With the Open Championship at Muirfield just a month away, he knows he must get back on track with a solid performance in front of his home fans in the Irish Open at Carton House next week.

He said: “I sound like a broken record, but I don’t feel like my game is that far away.   That’s what I’ve been taking out of this week.  It’s a matter of trying to let it all click into place.

“I’ve got one tournament between now and The Open Championship and that’s the Irish Open.  I’m looking forward to playing that.”

Padraig Harrington, meanwhile,  tees it up on the PGA Tour in this week’s Travelers Championship before heading home for the Irish Open.

Padraig Harrington plays his tee shot on the fifth hole during the third round at the 2013 U.S. Open at Merion Golf Club in Ardmore, Pa. on Saturday, June 15, 2013. (Copyright USGA/Michael Cohen) Tied for 21st at Merion, he was seventh for putting but failed to make an impact because he was 64th for birdies made and well down the field for ball-striking.

He said: “I was always on the edge all week where I never played the easy holes that well - I never made enough birdies to counteract the bogeys and obviously throwing in two doubles and a triple didn’t help.  

“It would have been a long stretch to get back to level par, but certainly I left a lot of shots out there.  I liked the challenge out there.  I didn’t find it that difficult at all.

“Some parts of my game are good and strong and I look forward to another week of getting ready for the Irish Open.  I certainly am glad it’s not next week though.”

As for Tiger Woods, who was 53rd for putting, Harrington is still backing him to win 19 majors and overtake Jack Nicklaus.

“Clearly he’s not as good as he was in the past, but he’s going to hit the right week enough times to win four more Majors,” he said. “He’s going to hit the right week eventually.”