Rory McIlroy laments 'turning good days into average ones'

McIlroy's round left him at four over par for the tournament following opening rounds of 72 and 72 - well out of contention, given that the leaders were nine shots ahead of him as he finished.

The Northern Irishman missed seven makeable birdie putts on the back nine alone, however, and adopted a weary air as he discussed his day's work in a post-round interview with Sky.

"I think it's the best I've hit the ball, pretty much all year," said McIlroy.

"I said yesterday that I felt I should have had a couple of 68s instead of a couple of 72s. I've developed a habit of turning pretty good days into very average ones."

McIlroy appeared to completely lose his confidence with the putter - not unusual for the prodigiously talented but highly streaky player, but hugely frustrating in this instance given the importance of the tournament and how good the rest of his game is.

"I gave myself so many chances from inside 15 feet and didn't make one of them. Once you miss a couple it gets into your head," McIlroy added.

"I didn't let it go, I wasn't trusting myself, wasn't trusting the pace of the greens.

"And then when you start making tentative strokes you start to miss, because around here you have to hit it firmly for it to go in."