* "The problem is mine," says McIlroy
* Couple had already sent invites (Adds McIlroy quotes, details)
By Tony Jimenez
VIRGINIA WATER, England, May 21 (Reuters) - A glum-looking Rory McIlroy admitted it would be tough to focus on golf at this week's BMW PGA Championship after calling off his engagement to tennis player Caroline Wozniacki on Wednesday.
Just days after sending out invitations to their planned wedding, the 25-year-old Northern Irishman said he was not ready for marriage.
"There is no right way to end a relationship that has been so important to two people," the twice major winner said in a statement on the eve of the European Tour's flagship event at Wentworth.
"The problem is mine. The wedding invitations issued at the weekend made me realise I wasn't ready for all that marriage entails.
"I wish Caroline all the happiness she deserves and thank her for the great times we've had."
The couple, known as 'Wozilroy' to fans, announced their engagement on Twitter in January when McIlroy proposed following a New Year's Eve fireworks show in Sydney.
World number 10 McIlroy, looking clearly distraught, told a news conference later on Wednesday that he never had any thoughts of withdrawing from the 60th anniversary edition of the Wentworth event.
"I'm not going to lie," he said. "It's going to be really difficult but when I get inside the ropes I'm going to have to try and concentrate on the matter in hand.
"I made a commitment to be here and I thought my duty was to play in this event," added McIlroy who had been in a relationship with Denmark's 23-year-old former world number one Wozniacki for 2-1/2 years.
"Obviously it's quite a difficult time for Caroline and myself and I think the statement really said it all this morning. It was mutual and we both thought it was the best for both of us.
"It's time to move on and I think I've said all I need to say. I just want to get my head into golf this week and concentrate on the tournament and try and do well.
"I've been playing well and the form's been good. I want to dive straight into it and keep myself somewhat busy and just try and have a good week on the course."
One reporter tried to lighten the mood at the news conference by suggesting McIlroy was at least returning "to a golf course that you love".
Laughter broke out around the room and the Northern Irishman produced a brief smile before pulling down his cap and covering his face with his hands.
Media reports seven months ago suggested the pair had ended their relationship but neither party confirmed the break-up.
Last year was a troubled one all round for McIlroy who suffered a slump in form after ending his equipment contract with Titleist.
He started 2013 as number one in the world rankings and in January signed a 10-year contract with Nike that, according to media reports, is worth $250 million.
McIlroy was also involved in a lengthy legal dispute last year after splitting from his management team and was embroiled in a disagreement with American sportswear company Oakley.
The Northern Irishman, winner of the 2011 U.S. Open and 2012 U.S. PGA Championship, has missed the cut at the BMW PGA Championship in three of the last six years and is looking to improve that record this week.
"This is a beautiful golf course and I've got great memories of the place from watching the World Match Play here in the early 2000s as a kid," he said.
"I'm trying to go in this week with the mindset of not getting frustrated and not to be frustrated that I might only get to hit my driver two or three times a round and feel like my advantage of my length is taken away from me.
"I'm just going to try and accept that you've got to plot your way around this course and not be overly aggressive ... just sort of rein it in a little bit," added McIlroy.
"It's a great event. This tournament deserves the best players and the best field and it gets that. Hopefully I can put in a performance that's a little better than it has been the last few years." (Additional reporting by Michael Hann, editing by Patrick Johnston and Ken Ferris)