Although Eto'o released a public apology to his teammates and "all the protagonists" of the match, he did not specifically name Cesar.
"He phoned me and said he really regretted what he'd done," the Chievo man told the Gazzetta dello Sport.
"He apologised to me and my family. The head-butt was just a result of his tension. I immediately accepted. You can tell a real champion from that behaviour.
"Clearly in the moment of the match you're in a sort of trance and these things can happen, but understanding you made a mistake shows your intelligence. A personal apology is a sign of a real professional."
Cesar insists when they next cross paths, there will be absolutely no problem.
"It was a matter we had to clarify personally and with a cool head. I realised Samuel and Inter are going through a tricky time and tension can play nasty tricks on you. Eto'o proved himself to be a champion and I have already forgotten the incident."