José Mourinho has undermined his attempts to brush off Friday's renewal of hostilities with Pep Guardiola after allowing himself to be rattled by a local journalist who had pointed out his record against the Spaniard. The Chelsea manager angrily disputed the relatively unimpressive figures, only to later acknowledge they were probably right.

At the pre-match press duties at the Eden Arena, an agitated Mourinho, preparing for the Uefa Super Cup against Guardiola's Bayern Munich, was confronted with memories of his fierce clashes with his rival's former Barcelona side. Indeed, the first question on the eve of the game had set the tone by reminding him he had only won three times in 15 attempts against Guardiola while with Internazionale and Real Madrid.

"Your statistics are wrong as a start," he snapped back. "Very wrong, very wrong but I don't want to discuss that because it's not important. I'll just say it's wrong. Go there and see what happened with Inter in the Champions League semi-final. The league records in Spain, the Copa del Rey in Spain, the Super Cup in Spain. You are very, very wrong. You are wrong but it's not important. It's not me against him, it's club against club That's not important."

That prompted a spluttered apology from the inquisitor, who was brandishing Uefa's statistical pack, which did, indeed, detail the 15 meetings between the managers, with Mourinho having won three times, Guardiola seven and five other matches drawn. The Portuguese, for his part, has not seen his side keep a clean sheet against a team coached by his adversary since their first meeting, a 0-0 draw between Inter and Barcelona in the Champions League group stage in 2009.

"I just know that I won the Champions League semi-final with Inter [in 2010]," continued Mourinho, his mind ticking over and realisation dawning. "I won the Spanish Cup final in Valencia [2011]. I won the Super Cup in Spain [in 2012]. I was champion in Spain [in 2011-12]. I won the match of the title in Barcelona with Real Madrid. So, I don't know … Maybe you are right and I am wrong but I don't care. It's not important for me."

The confrontation rather sparked the pre-match preparations, with Mourinho making it clear thereafter that Friday's meeting – a rerun of the 2012 Champions League final at the Allianz Arena, which Chelsea won in a penalty shootout – had little to do with the two managers involved, and even threatening to call a halt to proceedings if questions did not move on from the subject. He rightly acknowledged that neither manager had played a part in securing the European Cup and Europa League that offered these clubs a chance of early season silverware.

Pointing to the badge on his white training top, the manager said: "It's white but it's Chelsea. If you want questions about Chelsea I'm here until four o'clock. If you want questions about Real Madrid and Barcelona, I'm not here. It's not about me and Pep. It's about Chelsea and Bayern Munich. It's about a Super Cup where the European champions are playing the Europa League champions. Pep is not a European champion and I'm not the Europa League champion. We're just coaching these teams. It's not about us. It's about Chelsea and Bayern."