Rory McIlroy can break into the world's top 10 and become the youngest winner of the BMW PGA Championship after firing eight birdies in a spectacular third round 65 at Wentworth.

The Ulsterman, 20, will go into the final round of the European Tour's flagship event in third place, just four strokes adrift of leader Paul Casey on nine-under par.

Casey has a three shot lead over Dane Sore Kjeldsen and a chance to leap to world No 3 after a third round 69 left him at the head of affairs on 13 under par.

McIlroy confessed that he has had to put the brakes on his naturally aggressive style but playing for postion rather than distance off the tee.

"I just tried to put the ball on the fairways and not be too aggressive off the tee," he said. "I do like to get the ball as close to the green as possible off the tee.

"But there are some times when you can't do it."

McIlroy started the day on two under par but raced to the turn in two-under 33 with a bogey at the tough third erased by birdies at the second, fourth and seventh.

He then caught fire on the way home, racking up five more birdies before finishing with a disappointing par five at the last.

McIlroy has failed to fire on all cylinders since he finished 20th in the Masters but after turning a potentially disastrous opening round into a level par 72 and then following it with a 70, he turned on the style on moving day and believes he can use his renewed confidence as a springboard to greater things this summer.

"Today could be the round that could put me in great form going into the summer," he said.

Graeme McDowell soared up the leaderboard with an early morning 68 despite suffering from a leg injury that forced him to withdraw from the Irish Open after a spectacular second-round 61.

The Ulsterman was worried that he might be suffering from a stress fracture that could cause him to miss six weeks of the season but was relieved when a scan came up clear.

"Walking is very uncomfortable. I'm in quite a lot of pain," McDowell said after carding seven birdies including a hat-trick from the 16th.

"I've got a tight, footballer-type strap on my foot and ankle and I'm on painkillers. Thankfully it's not affecting my golf swing much. That's the frustrating part because I'm hitting the ball nicely but it is painful shot-to-shot and it's affecting my concentration a little bit.

"It is going to take time to heal," he said. "I'm going to have to stay off my feet as much as possible. I'm keen to play golf. This week is very experimental to see how the strap and painkillers work.

"Hopefully I'll be okay for (the European Open at the London Club) next week," added McDowell, who last season won the Ballantine's Championship in South Korea and the Scottish Open at Loch Lomond.

McIlroy made his breakthrough in the Dubai Desert Classic in February and appears to have rediscovered some trust in his swing after three disappointing weeks in Hilton Head, Sawgrass and Baltray.

He's bee tipped by Tiger Woods to become world number one at some stage in the future and feels good about what hard work and talent has helped him achieve so far in his career,..

He said "It's still very early in my career, and to achieve what I have has been very good, but I've worked hard for it, and I was given the talent by someone, and I've made the most of it. I've tried to become the best golfer that I can be. 

"You know, I'm going to try and keep working hard and try to get better, but yeah, I mean, obviously I'm very thankful to whoever it was that given me the talent to try and make the most of it.

"It was very close (to my best today). As I said, I hit all the shots that I wanted to. I was fading it off tees, drawing it off tees, hitting all the shots.  It was very similar to the first round in Dubai where I was hitting all the shots and seeing it very clearly. I just trusted it 100 per cent today, and when you do that, usually play very well."

McIlroy knows that Casey will be tough to beat but believes that if he is forced to go for broke with six holes to play he might have a chance of putting some pressure on the Englishman. 

"It's tough to win golf tournaments," he said, remembering several close calls late last year. "It's very tough. You have to handle your emotions and handle your nerves. If I can trust my game the way I did today and hit so many good shots, I feel as if I can give myself a very good chance. Even if I am a few behind going into the last few holes, I know that anything can happen. 

"Paul is a great player. He's been playing very, very, very well this year. I think he started this year 41 in the world, and if he wins tomorrow, he's up to third. So just shows you how good a year he is having. He won in Abu Dhabi, finished runner-up to Geoff Ogilvy in The Match Play and then he won in Houston again. 

"He's been up there, he's been up there all the time this year, and he's been a fantastic player and he obviously knows this golf course very well and he's won around here before. He's got good memories from it.
I expect him to be -- he's probably the toughest guy to beat out there tomorrow. If I go out and shoot another 65 tomorrow, I would like to think that would have a good chance to win."