Joshua and Dubois will meet in a clash for the IBF world championship at Wembley Stadium, live on Sky Sports Box Office on September 21.

Fisher, the Southern Area champion who has regularly sparred with Dubois, does not see that fight going the distance.

“I think it will be a knockout. I think Dubois is going to bring the heat and put it on Joshua. That’s what he knows, that’s his way. He’s an aggressive fighter but he’s calculating that aggression,” Fisher told Sky Sports.

He knows Dubois is dangerous. The Londoner is the heaviest puncher Fisher has been in the ring with.

“I’ve sparred him many, many times. He’s definitely the hardest puncher, Daniel Dubois. He can seriously whack,” Fisher added.

“Dubois takes no prisoners in sparring. You’ve got to be on it. It’s a firefight when you go in with Dubois.”

He cautioned that Joshua “has to be careful but he doesn’t have to be too cautious and too much on the back foot because I think Dubois is open to a counter right hand himself”.

“We’ve seen how good Joshua is with the counter right hand,” he continued.

“If he [Dubois] comes in, if he steps in too much, Joshua’s going to counter him with the right hand, like he did with [Francis] Ngannou.

“I know Ngannou’s not on that level but [Joshua] has got a good straight right hand that’s lethal. Charles Martin he’s done it against. We’ve seen it many times. That’s the danger for Dubois.”

A confident Dubois says he will put Joshua to sleep on September 21

Fisher continued: “If I am picking a winner out of that fight, I would edge towards Joshua. A little bit more calculated. A little bit more knowhow and nous in his game and I think that could tip it in his favour. But if Dubois lands on his chin, that could bring back all them memories [of the Andy Ruiz defeat] for Joshua.”

This Saturday, Fisher expects a firefight of his own against Alen Babic at the Copper Box Arena in London, but said: “I’d expect him to be right there in front of me, and that’s not a good place to stand.”

A strong performance, he believes, could put him in the equation for a British title fight with Fabio Wardley or Frazer Clarke.

“You win the next fight and the picture becomes a bit clearer,” Fisher said. “I think people are starting to see that there’s potential there to go beyond just being a ticket seller. I’m a prospect and I’ve got the potential to maybe win an English, British title, maybe European title and who knows I might even fight for a world title. That’s what you want to get to. That’s the aim.”

Clarke and Wardley fought each other to a draw in an epic British heavyweight title fight in March. Negotiations for a rematch are ongoing.

Dubois is confident he has what it takes to defeat Joshua

“Fabio Wardley I’ve sparred loads, Frazer I’ve sparred before and I just have admiration for both of them guys. They really did the belt justice that night,” Fisher said.

“Frazer Clarke I think showed a lot of mettle in that fight. It’s really hard [to predict] because there were points where I think if someone just trained five per cent harder, or their fitness was one per cent better it could have tipped the balance.

“I think Fabio’s got that danger streak in him where he can just unload and it could be over within the first round. But I think the nous and the knowhow is with Frazer Clarke.

“I think it would be Fabio short distance because he did knock him down, if not, if it’s going long, Frazer could beat him on points next time.

“It really is one of them fights you can’t really pick until the night and then you see how the fight unfolds.

“That’s why heavyweight boxing is so exciting.”

Don’t miss Anthony Joshua vs Daniel Dubois live on Sky Sports Box Office on September 21