Lewis is now a respected boxing pundit for American television
Hatton v Mayweather
Date: Sunday, 9 December
Starts from: 0100 GMT
Location: Las Vegas
Watch: Sky pay-per-view
Listen: BBC Radio 5 Live
Updates: BBC Sport website and mobile
Lennox Lewis has warned Ricky Hatton he must knock Floyd Mayweather out within four rounds if he is to win Saturday's WBC welterweight showdown in Las Vegas.
Former world heavyweight ruler Lewis says fellow Briton Hatton has "a good chance" to beat American Mayweather.
But he told BBC Sport: "Ricky's got to go in there like a madman and, no doubt, he must go for an early win.
"Hatton has to rough him up, get Floyd up against the ropes and not give him room. Maybe then he can do it."
Undefeated pound-for-pound star Mayweather, 30, has won six world titles in five different weight classes, and Lewis insists he must be clear favourite for the MGM Grand super fight.
I just hope referee Cortes allows Hatton to get inside because that will be his best tactic
But Lewis, who with Muhammad Ali and Evander Holyfield, is one of three boxers in history to have won the heavyweight title on three separate occasions, expects Hatton will not give up his own unblemished record lightly.
"Floyd is obviously the favourite because he is so quick and has such great boxing skills," the 42-year-old said.
"He has great movement and no one yet has really been able to catch up with him or really figure out the puzzle surrounding him.
"But I'd love to see Ricky do it. It would be a real accomplishment and put him up there with the great all-time fighters, but to win he must impose his will on the fight."
Former featherweight champion Barry McGuigan believes referee Joe Cortez will have a major say in how the fight pans out.
McGuigan said: "Ricky will have to have the fight of his life on Saturday.
"And I just hope referee Cortes allows him to get inside because that will be his best tactic.
"Mayweather has such brilliant hand speed and I think he'll be just too quick. But I'm worried he will use the referee and pickpocket the fight."