I’m not clear how this case can be pursued, given that she accused him and he denied it - to then claim that the denial (absent specific attacks against her) is defamatory is extra-judicial jeopardy against a criminal charge.
I’m not addressing whether there was a rape or not, just that denying having committed a crime doesn’t seem a valid basis for defamation.
Its the rat trap.
She calls him out for the rape. He denies it because he says she is a liar. She sues. He has to prove she is a liar in order to avoid defaming her.
Simple. He chose to call her a liar, he takes his chances. If her statement wasn’t true, he could have sued her. He didn’t.
He could have kept silent. He didn’t.
He is screwed now.