A series of poor performances in 2013 may be starting to take their toll on former world number one Rory McIlroy.

The Northern Irishman was the perennial Paddy Power favourite in virtually every tournament he played in last year, but since switching to his new Nike clubs at the start of the season on the back of a lucrative sponsorship deal, he has consistently struggled for any kind of form.

While McIlroy's tied for 41st finish at last week's US Open can hardly be called a surprise, his reactions at times during his final-round 76 was.

McIlroy has always kept his negative emotions in check on the course, but at Merion on Sunday he was caught on camera throwing a club away in disgust at one hole, then bending his nine iron so badly after a poor tee shot at the 11th that he couldn't use it for the rest of the round.

Such frustration is perhaps understandable for a young golfer who has already set himself such high standards, and after his round McIlroy had clearly calmed down, once again exhibiting a positive outlook.

"I sound like a broken record. But I don't feel like my game is that far away," he said. "It's a matter of trying to let it click into place."

Asked about the nine iron situation at the 11th, he replied: "I just hit a bad tee shot into the creek there, and what you don't want to do as a golfer is follow one mistake with another, and that's what I did. And obviously I got a bit frustrated there.

"It's a hole that you want to try to take advantage of. It's a hole that you want to at least give yourself a birdie chance and you walk off with a quad and it's not very good.

"I think that's what this tournament does to you. At one point or another it's got the better of you, and it definitely did this weekend."

McIlroy did, however, admit he was finding it hard to adjust to his new Nike clubs.

"It's definitely a different feeling," he said. "The thing about new equipment is you can stand on the range all you want and hit balls, but you really need to test it on the course.

"The numbers could be great on the computer, but you need to get out and test it in competitive play and that's something I didn't do at the start of the year. I only played twice by the end of February, 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. It's hopefully something I'll never have to do in my career again."

Do you back the two-time major champion to get to grips with his new clubs and start winning tournaments again soon? Or do you think the Ulsterman is in for more trying times while Tiger Woods continues to dominate? Either way, you can bet on golf and back the world's best as the 2013 season rolls on.

Golf 365