Italian defender concedes he did make an offensive remark.
Materazzi, 32, told Gazetta dello Sport: "I held his shirt for a few seconds only, then he turned to me and talked to me, jeering.
"He looked at me with a huge arrogance and said, 'If you really want my shirt, I'll give it to you afterwards.' I replied with an insult, that's true.''
Materazzi has not elaborated on what he did say, but one report suggested he responded with: "I'd rather take the shirt off your wife."
He has denied, however, some of the more vile insults referring to his wife or sister or calling him a terrorist.
"It was one of those insults you're told dozens of times and that you often let fall on a pitch,'' Materazzi said.
"I did not call him a terrorist. I am not a cultured person and I don't even know what an Islamist terrorist is.''
He added: "For me the mother is sacred, you know that.''