WBA and IBF world heavyweight champion Anthony Joshua has threatened to “freeze out” Deontay Wilder unless the WBC title holder stops “hooting and hollering” about a future bout.
Their promotional teams met in late 2017, but the American’s manager Shelly Finkel has said Joshua’s promoter Eddie Hearn has not been in touch this year.
Briton Joshua, 28, faces WBO champion Joseph Parker in Cardiff on 31 March.
“Wilder has to be realistic and stop living the fantasy,” he told BBC Sport.
“If he was serious about the fight, we’d do serious negotiation. If not, stop hooting and hollering because we’ll just freeze him out.”
Joshua – undefeated in 20 bouts – could hold three of the four recognised titles if he overcomes New Zealand’s Parker, who has 24 wins from 24 fights.
His promoter Hearn says he is “nervous” for what he calls the “toughest” fight of the Briton’s fast-moving career.
And, after conducting skipping, shadow boxing, pad work and some neck-strengthening exercises for the cameras at an open workout on Wednesday, Joshua told BBC Sport that he hopes to improve his weight management leading up to the Parker fight, at the Principality Stadium.
He weighed a career-high 18st 2lbs when defeating Carlos Takam in October.
“Around this time in my last camp, I was around the same weight I am right now,” he said.
“I don’t know how I shot up in weight in fight week. Maybe I relaxed, maybe I was so exhausted that I lay on the bed eating. It went on so easily. I spent three months training everyday and then for a week did little.
“I’m learning. Fight week is as important as camp. I won’t be coming in that heavy, I really doubt it.”
After the Takam victory, Joshua said the added weight felt like carrying two newborn babies on his shoulders.
His nutritional team – who ply him with around 3,000 calories on easy training days and 5,000 on tough ones – insists it is not an issue and that ensuring he has high energy levels as a result of his diet is more important.
Joshua’s camp point to his diligence in adapting his preparation after each fight and he insists the weight issue is another example.
“Faith is stumbling but still knowing your destination,” Joshua told BBC Sport’s Mike Costello.
“Sometimes if you stumble, people say ‘he’s no good, he doesn’t have the strength to get back up’. People have pictures of people they admire but they don’t know how many times they failed.
“Everything nowadays is about the highlight reel and it has to be perfection. It’s important to share your struggle, not just your success.”
‘Shut out the noise’
Joshua’s trainer Rob McCracken says a late change of opponent last October, from Kubrat Pulev to Takam, impacted upon his fighter’s motivation.
Yet he still scored a 10th-round stoppage against a fighter who took Parker the distance in 2016.
Some pundits questioned the referee’s decision to stop Takam, while others expected more from Joshua following his enthralling win over Wladimir Klitschko six months earlier.
Joshua said: “What I realise is that nowadays there are so many opinions and voices. If you keep listening to everyone’s opinion, how will you ever believe in yourself?
“If I do, when it’s time to tell myself who I am, I won’t believe in it. I have to be confident against Parker.
“I will be back in here later today sparring. I’ll have to deal with fast guys for 15 rounds. I have to learn, to perfect everything. That’s why I’m confident.
“It’s not overconfidence, I’m not thinking because I beat someone last year I can beat Parker this year.”