Chris Eubank Jr told Liam Williams 'you are going to get obliterated' during a heated exchange at the BOXXER press conference in London on Wednesday.
Eubank Jr, 32, will travel into enemy territory to take on Williams, 29, at the Motorpoint Arena in Cardiff on December 11.
For the last few weeks, Williams has been taking Twitter shots at Eubank and his father Chris Eubank Sr, who retired with a ring record of 45-5-2 (23 KOs). Williams previously insinuated that Eubank is only where he is today because of his surname.
Junior, who is 31-2 with his only losses to former world champions George Groves and Billy Joe Saunders, feels Williams has crossed the line with some of his statements.
"He has said a lot of reckless things online and it doesn't sit well with me at all," said Eubank, as the two exchanged words with each other.
"Respect is definitely not a word I would use for my feelings towards Liam," he continued, which provoked a reaction from the Welshman.
"He has said a lot of reckless things online. It doesn't sit well with me.
"This is a grudge match, a genuine domestic rivalry. It is personal. He has made it personal.
"He has come here today and tried to talk about respect? It has gone too far past that now.
"He will pay for what he has said. He will get embarrassed."
Williams, who is coming off a decision loss to Demetrius Andrade, has made clear his dislike for Eubank, judging by some of his social media outbursts in recent weeks.
However, when confronted about why he dislikes Eubank so much, Williams offered very little in the way of explanation, other than saying, "We're not each other's type of person.
"I don't have much respect for him personally. I don't like the way he goes about his business.
"He's not my type of guy. He's not somebody I'd want to be friends with.
"I've said a couple of things to him online. Things I stand by.
"If he doesn't like it, who cares? I don't."
Later on, Williams was asked how he plans to approach the fight itself, to which he curtly replied: "We all know what his strengths and weaknesses are.
"Anyone with a good jab and a bit of movement he'll struggle with.
"If you stand in front of him with no head movement, he will punch holes in you.
"He's very tough and durable."
In a rare flash of anger, Eubank responded by saying his boxing skills are far superior to that of his opponent.
"You are going to get obliterated," Eubank said.
"It will be a fun fight. The styles we have will gel well. He doesn't have what it takes to stop what I will do. Eventually I will get to him.
"Either he will quit or get knocked out.
"With his style, I don't see it going 12 rounds. He's got heart, will, determination. But that heart will get him hurt.
"He talks about game-plans and strategies? That won't save you. You don't have the skills."
Williams' last fight didn't go so well, with Andrade outpointing him to improve to 30-0 (18) in April. But that didn't stop him from having the final say, which prompted a few laughs from the audience.
"He knows how to talk, he's a pretty good talker," Williams said, before referencing Eubank's famous father and adding, "His daddy must have paid for lessons, but he needs to prove himself."
Chris Eubank Jr vs Liam Williams will air live and exclusively on Sky Sports, with tickets available to purchase via boxxer.com/tickets.