The Cat hopes Haye has learnt his lesson
Pain is relative, so when Carl Thompson tells you David Haye hasn't been tested since he beat Britain's current heavyweight world champion back in 2004, it would be foolish not to take into account Thompson's stratospheric threshold.
There were times when watching a Thompson bout was like watching a sculptor working with a set of children's tools, his opponent's blows ricocheting off all parts until the tools were bent and broken and pretty much useless.
"I was thinking, 'I'm going to knock him out'," says Haye of the night he suffered his only professional defeat to date. "And it didn't happen." "I was a very hard person to fight," explains Thompson. "To David that fight was hard, to me it was just an everyday thing."
Six years earlier Thompson had brought Chris Eubank's career to a juddering halt, and only a few months before his fight with Haye, Thompson was pulverised for nine rounds by South African Sebastiaan Rothmann before dredging up a huge right hand and turning the fight on its head. Unlike the cricketer Phil Tufnell, Thompson was nicknamed 'The Cat' for his infinite lives rather than his ad hoc sleeping habits.
Carl Thompson (right) stopped Haye in five rounds when they met at Wembley in 2004
In his fight against Haye he was very nearly stopped in the first, before Haye blew himself out and Thompson blew him away. "I learned my lesson not to be complacent a long time ago," says Haye, "but it's still fresh in my mind." Fresh as a gale force wind.
On Saturday in Manchester, Haye makes the first defence of his WBA heavyweight crown against two-time world champion John Ruiz, but Thompson, still dreaming of a comeback at the age of 45, is yet to be convinced of his old rival's credentials, uncertain the lessons have been learnt.
"David needs to show me a little bit more to prove to me he has learnt because the people he has fought since me haven't really tested him," says the former cruiserweight world champion.
"Even when he beat Nikolay Valuev for the world title, that big guy, 7ft 2in, never used his height or weight advantage, he didn't use anything, he just let David take the belt off him.
"I'm a very hard person to please, but if John Ruiz can test him a bit more and David can beat him, then that would go some way to proving I at least taught him something."
While Thompson was 40 when he defeated Haye, the grizzly Ruiz is 38 and a veteran of 53 pro fights (44 wins, eight defeats and one draw), 10 of them with a world title at stake. His clinch and grab style has made him perhaps the most maligned fighter of his generation, yet the truth is he has one of the most impressive resumes of any heavyweight fighting today (which, critics would argue, only goes to show how far the division has fallen).
In a career stretching back to 1992, Ruiz has been in with Tony Tucker (won), Evander Holyfield (one loss, one win, one draw), Roy Jones Jr (lost), Hasim Rahman (won), Andrew Golota (won, despite being down twice) and Valuev (losing narrowly twice). Win, lose or draw, even his harshest critics would have to admit 'The Quiet Man' brings a tremendous amount of experience to the party.
Ruiz has trimmed down to 16st and hopes 50 punches a round will make him a blur for Haye
"There are similarities," says Thompson. "I knew I could beat David because I knew he had never been in hard fights like I'd been. When he came up against me, he must have been shocked, and Ruiz will be hoping for the same."
Ruiz's new trainer, the venerable Argentine Miguel Diaz, says his charge will be boxing rather than wrestling at the MEN Arena, while Ruiz himself, who has been whittled down to 16st, has spoken of taking Haye out of his comfort zone by throwing 50 punches a round. It is a tactic Thompson approves of, but he is not convinced Ruiz has what it takes to follow it through.
"John Ruiz is similar to my style in that he will come forward," says Thompson, "but coming forward is not necessarily the same as applying pressure. I applied a lot of pressure, even when David came at me I still came at him.
"How you fight David is you let him steam at you, try to blast you out, and then you've got to attack him straightaway, so that you're forcing him to work when he doesn't want to work.
"That's the key for John Ruiz, but I don't know if John is capable of doing that, making David fight when he doesn't want to fight. It's a bit too late for changing things now, and I'm not sure John ever had what it took in the first place."
"He'll be thinking that, coming forward, getting through the early onslaught, he'll try to get me in the second half of the fight," says Haye. "But he doesn't realise that early onslaught is going to be so extensive he'll be lucky to be there for the second half of the fight.
"I have to see John Ruiz as the toughest fight of my life, simply because he is. If I lost to John Ruiz, it would be catastrophic. All that hard work, the win against Valuev, would mean nothing.
"I've got to produce the same performance as I did against Valuev, pure class, pure skills, and I'm positive I will get the knockout. I'm going to have to produce something special to get him out of there, but I will do it."
There's a great line from BBC commentator Jim Neilly, just as Haye is starting to wane against Thompson: "Is he going to get a lesson from an old fella whom everybody has just about written off?" He could have been speaking about Ruiz - we'll find out on Saturday whether The Cat's lesson has been learnt or not.