Holyfield, the World Boxing Association and International Boxing Federation heavyweight champion, is not normally outspoken but insisted: "I am not predicting it, I am telling you".
The American's statement revealed a determined edge before his showdown with Lewis at New York's Madison Square Garden on 13 March. Lewis has thrown a few remarks in Holyfield's direction during the last week and has accused the double champion of "ducking" him until the mega-fight was made.
Holyfield added: "Lennox is a good fighter. Lennox will do well. I'm still gonna knock him out. Now you just have to wait and see if Evander tells the truth. I've opened my mouth and now I have to knock him out."
Holyfield, who will give away about 30lb and three inches to Lewis, says he was putting himself "out on a limb" with his prediction in order to have the world judge "if the man of God is true." He added he wanted "people to see the changes God made to my life."
Holyfield's prediction of a knockout could also be an attempt to pump himself up for the fight against the strong, but technically impaired and often passive Lewis. "People always try to find a reason to make themselves feel better about themselves," said Holyfield, when asked about Lewis calling him a hypocrite for espousing his religion while fathering children out of wedlock.
Lewis's criticisms "don't make me any smaller", Holyfield said. The question is whether a person "can overcome mistakes he's made and I have. I'm not ashamed of what I've done. Lennox Lewis is a defeated foe. He knows that and those who don't will find it out on 13 March."
Holyfield said Lewis had been daring him to fight him and, now he had his wish he would be facing "his worst nightmare." The man who beat Mike Tyson twice brushed aside any earthly reason for retiring.
"The only [time] that I'll consider leaving is when the Lord has released me from boxing," said Holyfield, who will be paid pounds 12m for the fight. Lewis will get pounds 6 million.
Holyfield added he continues to fight "for the purpose of spreading The Word. God will let me know" when to quit. "It's not fair because he don't have a chance to win." Holyfield said of Lewis. "Whatever I do [in the ring] he won't be able to stop it."
Holyfield added that the question of Lewis's stamina in the later rounds is irrelevant because, "the fight won't go that long. Everybody gets tired, it's what you do when you get tired."
The former heavyweight boxing champion Mike Tyson, in gaol for assaulting two motorists, will spend 25 days in solitary confinement as punishment for hurling a television set at prison guards.
A Montgomery County Detention Centre disciplinary panel also took phone, television and visitation privileges away from the 32-year-old fighter. The boxer will spend 23 hours a day in solitary confinement until mid- March.