Unbeaten American Deontay Wilder says he is pushing David Haye to the limit in sparring ahead of the Briton's showdown with Tyson Fury later this month.
Haye continues to keep his training schedule under wraps ahead of the Sky Sports Box Office fight on September 28 but Wilder, who boasts 29 wins from as many fights - all by knockout - has revealed that he's not going easy on Haye, placing particular emphasis on improving the 32-year-old's speed.
"I got him ready for the Wladimir Klitschko fight when he fought for the title and now I'm here again," said the world heavyweight contender. "I like working with David and Adam Booth - they are great guys.
"David is looking great, really great - he's working super hard. It has been said that this is the hardest camp that they've ever had.
"When I come to spar I definitely come to spar, I definitely come to fight. Don't get me wrong - there's nothing light in sparring; we're not going light on each other, tapping each other.
"We're definitely going for speed because we know he's in for a big fight with a big guy who is going to use every ability and tool that he has for his height and his weight, so we want to push him to the point where he can't go anymore."
Sky Sports pundit Jim Watt says that Haye has shown his hand by bringing in sparring partners of Wilder's quality ahead of the Manchester Arena clash, and feels that the ex-WBA heavyweight champion is fearful for his legacy.
"I think David Haye feels a lot of strain with this one," Watt told Ringside.
"David would have excuses for losing some of his previous fights but I think he sees a lot of his achievements are on the line here against Tyson Fury - it's like a bad night here could tarnish what he's achieved. He's had a terrific career too.
"But I think that he's worried about losing this one - and that probably makes him a little bit more dangerous.
"David isn't bringing in sparring partners, he's bringing in guys who have a career of their own and still want to make a name for themselves.
"Having said that, Fury has brought in some sparring partners. He's tucked himself away abroad, so he's taking the fight equally seriously.
"I like the way Fury went looking for this fight - he really fancies the job and has shown a lot of confidence and he's actually silenced David at press conferences and such, which is really surprising. I think he's turning into a little bit of a character."
David Haye's heavyweight clash with Tyson Fury is live on Sky Sports Box Office on Saturday, September 28. Programme begins at 8pm.