The Open: Rory McIlroy in upbeat mood for Royal Birkdale

Rory McIlroy has insisted his game "is all there" as he heads into The 146th Open at Royal Birkdale with a positive attitude despite his poor run of results.

McIlroy's season has been disrupted by a rib injury which he first sustained in January and aggravated at The Players Championship in May, but his return to full fitness has coincided with errors creeping into his all-round game.

The world No 4 missed the cut by a distance at the US Open and also failed to make the weekend over the last two weeks at the Irish and Scottish Opens, although he steadfastly maintains he is very close to rediscovering his best.

"Tom Weiskopf is the one that said that first. He said, 'when I'm playing well, I can never imagine how I ever played so badly. And when I play badly, I can never imagine how I played so great'," said McIlroy at his pre-tournament press conference.

"And I think that's how fine the line is in golf, between playing great and playing poorly. Right now I feel like I can hit the ball in the fairway, and from there I can hit the ball on the green. And if I get my eye in, I can put the ball in the hole from there.

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"So it's not bad. It's not as if I can't see myself shooting a good score. It's all there. It's just a matter of putting it all together. My memories of golf are pretty good right now. I've done some pretty good things in this game, and I don't feel like I'm that far away from doing them again.

"My game is all there and it's just about staying as positive as I possibly can. I don't know if I'll find something this week, I'll be able to tell you better when I'm in the tournament and how I'm feeling out there. But I'm as positive as I can be, I guess, and we'll see how that goes."

McIlroy was widely expected to be the dominant force in golf after his outstanding 2014 campaign in which he won his first Open title and followed that with his second PGA Championship win at Valhalla, but he had not added to his four majors since.

"When you ride on the crest of a wave, it's easy to get caught up with those expectations and you start believing them," he added. "I have been able to play golf in stretches that if I continued that type of golf for six, seven, eight years, yes, I would be able to win a lot more.

"But golf is so fluid and so you're always trying to evolve. You're always trying to figure out what the best way is to get the best out of yourself, and the thoughts that I might have had when I won at Hoylake might not work for me now. It's all about trying to get the best out of yourself and trying to think about what thoughts you need going into the week.

"If you had the same thoughts and the same feelings each week and that's what worked for you every single week, the game would be easier than it is. But golf is almost like life, there's ups and downs, and it's never that linear sort of direction.

"But when I won those three tournaments in 2014 and I was where I was in the game, of course I thought I really can keep this going and I was going into the Masters the next year thinking I can win the Grand Slam, and some things just come along that you don't expect.

"There's been a couple of injuries the last couple of years, and that sort of stopped me in my tracks. But I've still got plenty of time to rekindle those feelings and that sort of play. And I really don't feel I'm that far away from it right now, even if the results don't suggest it.

"I wish I was here being the No 1 player in the world with a couple more majors and whatever, and I'm in a place where I'm trying to figure out how I get back to that position where I was this time two and a half, three years ago.

"But I'm working on it. I'm trying to get back there and I'm doing everything I can. And hopefully the start of that crest of a wave happens this week."