'Moves like a cardboard box on wheels': Keith Thurman roasts Brock Jarvis in colourful press conference

Keith Thurman roasted Brock Jarvis during a colourful press conference ahead of their fight on Wednesday with the American unfazed by claims he's too old.

Former welterweight world champion Thurman and Jarvis will step in the ring in Sydney on Wednesday night — and the former champ had no trouble holding his end of promoting the fight.

Jarvis, 27, stuck to the same line as he has throughout the lead up, that 36-year-old Thurman is an "old man" and "isn't the same as what he used to be".

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But Thurman went to some interesting places in dissecting his opponent and the drama he has endured over the past month.

Jarvis split with long-time trainer Jeff Fenech weeks out from the fight, although it's understood Fenech will be in his corner despite not attending the press conference.

"Your trainer left you because you don't know how to listen Brock," Thurman said.

"You had an old man training you who was already world champion and you can't hear the words this champion is telling you today. You might do great things but not on Wednesday night."

When asked about what he saw in Jarvis as a fighter,

"He moves like a cardboard box on wheels man. A Tetris board in action. He's square as f---. The boy got no head movement," he said.

"I'm a two-time world champion I've seen this time and time again. I'm not trying to underestimate him. I'm just dissecting who they put in front of me. He's square and thinks he's going to drop bombs on an old man."

In response, Jarvis said: "I'm gonna punch a hole in your head ... I'm gonna hit you, and I'm gonna hurt you."

"I'm shaking, I'm so f---ing scared," Thurman replied sarcastically.

The American then called his opponent a "muscle bound bitch boy", declaring that he will "whoop his ass".

Thurman, who holds a professional record of 30 wins and one loss, is aiming to leave behind several years of injury-laden struggles as he gets back into action after more than three years absent from the ring.

He told Main Event after the press conference that he has big plans in Australia, with Tim Tszyu in his sights.

"That's really why I'm here. I didn't come all the way over here for Brock Jarvis, you know— that's a nice little appetizer dish, or, as we say on Broadway, the opening act... I think it'd still be a great match-up for the fans."