George Groves has branded James DeGale a "child" ahead of their British and Commonwealth super-middleweight title showdown on Saturday.
The pair meet at the O2 Arena, London.
And their war of words shows no sign of letting up, with Groves the latest to throw a salvo.
"He's obviously not a man mentally, and I might go out and show he can't deal with a man physically either," Groves told the BBC. "He's a child in a man's game."
"I need to tighten up, I know my defence isn't perfect, but people need to concentrate not so much on the negatives and look at the positives as well.
"I was trying a lot of new stuff in the Kenny Anderson fight [Groves was floored on the way to winning the Commonwealth crown last November], new defensive techniques that didn't turn out quite right because I didn't have enough time to drill them.
"But I've learned from that and improved on that. I haven't just turned professional and tried to build on my main strengths as an amateur and neglected my weaknesses.
"I don't want to be a one-trick pony like James - he's worked on his attacking attributes, which is that he stays low and lets his hands go, but other than that there's not too much else to his game.
"Once he's taken out of his comfort zone, once he has to rely on his instincts, he's got no Plan B."