Former Liverpool goalkeeper Jerzy Dudek revealed he heard a "devilish voice" in his head telling him to punch Rafael Benitez in the face after the Spanish manager signed Pepe Reina in 2005.
While Dudek said ex-Liverpool boss Benitez was a genius, the Polish keeper was left fuming by his decision to bring in Reina from Villarreal just months after helping the Merseyside club to a memorable penalty shoot-out victory over AC Milan in the Champions League final.
Dudek - in an extract from him his new biography 'A big Pole in our goal' set to be released on Friday - wanted to leave for Cologne but claimed Benitez's poor man-management almost drove him to violence.
"I loved being at Liverpool, but Benitez clearly didn't want me. I'd been the hero in Istanbul so could I now just be a fire-fighter who waits for the moment when a fire needs fighting," Dudek said via The Mirror.
"Then rumours started that I was earning between £60,000-70,000 per week and Benitez wanted me off the wage bill."
The 43-year-old, who spent seven years at Anfield before retiring at Real Madrid in 2011, added: "The negotiations started. I was in touch with Cologne regularly and they told me Benitez wouldn't speak to them. I got more and more frustrated with him until transfer deadline day when I finally boiled over.
"As soon as training had finished, I stormed over to him and ripped my gloves off in an aggressive manner. I was so angry that the lads said later the aggression was pouring out of me. I raised my voice.
"The lads could see I was fuming, so all hung around to see what would happen -- footballers love seeing a bit of confrontation on the training ground!
"I was furious with him, absolutely fuming, and in my head I could hear a devilish voice saying 'Punch him in the face - punch him in the face and he'll let you go to Germany'.
"To be completely honest, I genuinely considered punching Rafa in the face. Then the consequences of doing so flashed through my mind. Would he let me go? Or would it just lead to a massive media scandal? Surely I couldn't stay if I gave him a smack?
"I don't know how, but I managed to stop myself. Punching a Liverpool manager who had won the European Cup only a few months earlier wouldn't have looked too good on the CV, I guess, but I was still angry."
Dudek continued: "As I walked off towards the dressing room, Stevie [Gerrard] walked alongside me.
"'You wanted to punch him, didn't you, lad? You really wanted to f***ing punch him...'"