But he insists he is not out of form - just that all his mistakes went punished.

Boruc made a number of high-profile errors, most famously when he mis-kicked a pass-back and allowed Northern Ireland to claim a 3-2 win over Poland.

The 29-year also found himself in trouble for breaching disciplinary rules for club and country, following the break-up of his marriage.

But he said: "I don't accept all this talk that I'm in bad form.

"Last season I made five serious mistakes in games for Poland and Celtic, which is roughly the same as I did the year before.

"But no one said it was my fault then, because those errors went unpunished. A lot comes down to luck - and sometimes your luck runs out."

Boruc was targeted by the Northern Ireland fans at Windsor Park but claims the abuse had nothing to do with him conceding two poor goals.

"My form in the match in Belfast when Poland lost 3-2 to Northern Ireland and the earlier game in Bratislava, when we lost 2-1 to Slovakia, was related to my personal situation," he told the Polish press.

"In Belfast, I wasn't scared of the Northern Ireland fans' taunting.

"I like pressure; I like when the fans are screaming at me.

"The influence on my performances in the Slovakia and Northern Ireland games was not fans, but my personal situation.

"Never mind if you are a worker in a factory or you are a goalkeeper playing in front of thousands of people every week - if you have personal problems it will affect you at work, no matter what you do."

New Celtic manager Tony Mowbray has held talks with Boruc, who has been joined at the club by international team-mate Lukasz Zaluska.

Mowbray said: "If Artur has any problems he needs to tell me. I also spoke to him about his motivational levels.

"He understands he's got to get down to some hard work in pre-season and get focused on the job."