"People saw in the last fight against Michael Sprott [Harrison won by 12th-round knockout in April], I fought the guy with one hand for eight rounds, so people said 'now we've ticked off this box, he's got a heart, he's got character'.
"But I've always had character, always had heart, that just gave me the opportunity to show it, and 12 rounds under those circumstances bodes well for this fight.
"I'm going to be standing on that starting line believing I can win, wanting to win and throwing shots like I want to win, and that's a different Audley Harrison.
"I've definitely got more than a puncher's chance because not only can I punch but I've got the pedigree, the right team who have taught me how to fight and I know the fundamentals of the ring.
"It's brain over brawn - David Haye is brawn over brain, he's a brawler, he likes to mix it, and you're going to see why it's called the 'sweet science'.
"I'm confident his best punch is not going to be able take me out and I'm confident my best punch can take him out.
When a man comes to you and says 'I was wrong, I apologise, I'm not like that now', your heart has to give in
Harrison's trainer Shadeed Suluki
"He's going to try and avoid my punches, but he can't do that all night, at some point he's going to have to taste my leather.
"It's not going to be a one-sided fight, at some point he's going to have to take some punches and we'll see what happens from there."
In addition, Harrison believes the British public are coming over to his side having bought into his story of "perseverance" and "true British spirit".
"I've been booed at boxing matches but walking down the street I've had nothing but autograph requests, people telling me to keep going," said Harrison, who has been beaten four times in 31 professional fights.
"The majority of the British public aren't boxing fans, they're Audley fans because I won an Olympic gold medal for the country, so they've stayed with my story.
"I've overcome the odds and now it's starting to build to the crescendo where people are thinking, 'this guy might do it'.
"The story resonates with people because we've all got dreams and hopes and desires and all I've been is a man who's stuck to his guns, never given up.
"And now I've got an opportunity to finish my journey, complete the mission, win the world heavyweight title."
Meanwhile, Harrison's trainer Shadeed Suluki claims he has seen a genuine change in his fighter and that his setbacks had, indeed, made him "more humble".
"He's matured, he knows where he went wrong and he's corrected that," said the American, who last week questioned the credentials of Haye's trainer Adam Booth.
"It takes a man to admit where he's gone wrong and that's why he knows where David is, where his ego is, because his ego was as big back then.
"You see a different Audley now, even in training - he usually likes to run things, but in this camp he gave me himself, he said 'what do you want me to do? I'll do it'.
"You can see and hear the sincerity. When a man comes to you and says 'I was wrong, I apologise, I'm not like that now', your heart has to give in. You've got to give them a chance, and the British public are giving him a second chance."
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