James DeGale has continued his war of words with George Groves by dismissing his bitter foe's trainer Adam Booth as a "glorified Fitness First coach".
The London rivals meet at the O2 on Saturday in an eagerly awaited showdown for the British and Commonwealth super-middleweight titles.
Insults have been flying since the fight was announced and the animosity between the former Dale Youth ABC stablemates - Groves beat DeGale in their only meeting as amateurs - is genuine.
Booth, who also trains WBA heavyweight champion David Haye, was caught in the crossfire when DeGale questioned his credentials.
"As a professional George has got worse. He was better in his first three or four fights," said the Olympic gold medalist.
"I don't know why he's gone backwards - maybe it's his training or his trainer.
"Adam Booth is just a glorified Fitness First coach.
"I don't rate him as a trainer. I heard he boxed as an amateur, but pulled out of a lot of fights.
"My trainer Jim McDonnell has been there and done it, he sacrificed himself and did the hard work.
"Listen, if I was in the corner with Haye he'd be a world champion. David's talented, he's good and has ability.
"Booth and Haye are business partners, that's all they are. I think they've come up with this gameplan for George, but it's just annoying.
"George is trying to be too much like David Haye. He's a wannabe David Haye, but that isn't him.
"He's a come-forward, aggressive fighter and that's what he should stick to because that's what he does best."
DeGale has raced to 10 victories since making his professional debut in February 2009 and has looked highly impressive in recent outings.
The 25-year-old's standout moment so far was stopping the vastly more experienced Paul Smith in the ninth round last December to seize the British title.
Groves, who is two years younger, has fought 12 times but his unblemished record has been tainted by a troubled performance against journeyman Kenny Anderson in November.
Flaws in Groves' technique were exposed by Anderson and the performance has contributed to DeGale's position as clear favourite.
"People are talking about this fight because there's genuine dislike between us, it's a genuine grudge match," said DeGale.
"The bad blood is real, we don't like each other. It goes back years and that gives the fight a different feel to it.
"That defeat in the amateurs is the only thing he's got on me. I don't think I lost it.
"I thought I was so far ahead that I took my foot off the gas in the last round.
"I was showboating, sticking out my chin. Maybe the old judges didn't like it - they're all 70 or 80 years old.
"I'm glad George beat me because if he didn't, we wouldn't be in this situation now.
"All the mind games, the banter, the needle - I love it. I know this is getting to George. The trash talking is part of boxing. If there were two George Groves' at a press conference, this fight wouldn't sell."
DeGale is prepared to bury the hatchet after Saturday's contest.
"Of course I'll shake hands with him after, win or lose," he said.
"I don't know if it will be the end of the bad blood though, you'll have to ask his camp. I just want to scratch this itch and then I'll move on in my career."