You could try for a long time to get Dereck Chisora to say something nasty about David Price, but he won't bite. However, the fact that Chisora likes Price won't mean he has any intention of going easy on his Liverpudlian opponent at the O2 arena, London, on Saturday night. This is fight week, after all, and the monster is emerging in Chisora.

Price stepped in at three weeks' notice to face Chisora after Joseph Parker, the former WBO heavyweight champion and his original opponent, was ruled out, apparently after being bitten by a spider.  But the change of opponent has not led to a let-up in Chisora's preparation.

"Come fight week, everything goes out the window, man," Chisora said. "Best friend or not best friend, I’m coming to destroy you. After that we can shake hands and love each other, fight week it’s war."

The two have moved in similar circles since they were amateurs. They both won the ABA super-heavyweight title, Price in 2005 and 2007, Chisora in 2006, when Price did not enter, because it clashed with the Commonwealth Games in Melbourne, where he claimed gold.

They also both held the British title, Price claiming it in 2012, a year after Chisora had lost the title to Tyson Fury.

Despite that, the pair have never been close to boxing each other and what rounds  they did share in the ring, as sparring partners, are now so distant as to count for anything.

"It was very good sparring, you would have paid money to watch that," Chisora said. "It was about seven years ago. A lot has changed. He might look at my old fights, my new fights, those spars, but fighters are different when you get in there. You never know what you might get. I like to change the way I fight every time.

"A couple of names were put forward [after Parker withdrew] and I thought if that’s the case then lets get David Price. He took it and I thought, ‘yeah’. He’s always in shape.

"It's a different fight to Parker, but I still fight the same way. Parker tends to mess around if you let him mess around

"I think it’s a bigger fight in London, for the British public. Parker was a bigger fight globally but for the Brits this is a bigger fight."

Chisora is well aware that a defeat to Price could end his claims to be a top-class heavyweight, but has never been one to swerve a match.

"There’s always a  bigger stake in every fight you take," he said. "Every loss you have on your record, that is when your money goes down. If you win it goes up! You never know it might be your last fight. David Price is a big puncher, if he lets that right hand go he can put anyone to sleep."