Paul Breitner has slammed Hans-Joachim Watzke over the loan row between Bayern Munich and Borussia Dortmund, saying that he did not expect the Schwarzgelben CEO to be such a "sore loser".
Watzke claimed earlier this week that the Bavarians had demanded an eight per cent interest rate on the €2 million (£1.7m) that they gave their then-cash-strapped Bundesliga rivals in 2004.
However, Bayern president-in-waiting Karl Hopfner said that this was an "absolute untruth", sniping that to compare Watzke to Baron von Munchausen, a fictional character renowned for his fantastical stories, "would be flattering to Watzke".
Breitner has now weighed in, revealing that he has been left disappointed by Watzke's behaviour, which he feels has made the Dortmund CEO look petty and bitter.
"He has made a mistake there," the former Bayern ace told the Rheinischen Post. "I would have expected more from him; not to have been a bad loser.
"This is honestly a shame. Why Mr Watzke has stepped into the ring, I cannot say. Annoyed or frustrated - whatever it is - it's not our problem."
Bayern face Dortmund at the Allianz Arena on Saturday evening, with the top-of-the-table clash set to kick off at 17.30BST.