UFC president Dana White says whoever wins Saturday's trilogy clash at UFC 252 will be the "best heavyweight ever" in mixed martial arts.
Stipe Miocic and fellow American Daniel Cormier, 41, meet for the heavyweight title for a third time in Las Vegas.
Miocic, 37, lost the belt in 2018 before winning it back in 2019, with both fights won by knockout.
"It's the best trilogy," said White. "You don't see heavyweights go at it the way they have in the first two."
Cormier claimed a first-round knockout at UFC 226 to become a two-weight world champion and was dominating their second clash at UFC 241.
Then Miocic switched his approach to attacking Cormier's body, which resulted in a dramatic fourth-round knockout.
"Cormier catches him with that shot in the first fight then in the second he was lighting Stipe up with some big shots," White added.
"But he goes back to the corner, they make some adjustments, and to come out and do what Stipe did, you see that stuff in the movies."
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Cormier aims to retire on a high
Cormier, who was light heavyweight champion before stepping up a division to face Miocic in 2018, goes in with a professional record of 22-2.
And the former wrestler hopes to end his career on a high having said he will retire after this fight.
"Peyton Manning won a Super Bowl in his last season," said the 2004 Olympian. "Michael Jordan won with the [Chicago] Bulls - unfortunately he came back, I won't.
"When I win on Saturday, I will retire that way. It would put me in the same sphere as some of the greatest athletes in any sport."
Miocic aims to make his fourth title defence and has a 19-3 record, with the loss to Cormier his only defeat in his last eight fights, going back to 2014.
"Getting that belt back was everything but we've got unfinished business," he said. "I've got no ill will towards the man. He's going to retire and I wish nothing but the best for him."
'Welcome to the Sugar Show'
The co-main event sees rising bantamweight star 'Sugar' Sean O'Malley face Ecuador's Marlon Vera in a "striker versus grappler match-up".
The unbeaten American, 25, sees 'Chito' Vera as his "toughest fighter to date", with the 27-year-old having never been finished during a 15-6 career.
"With that said, I'll probably still drop him first round," added O'Malley, who is 12-0 with eight knockouts.
"He has a ton of experience but whenever I fight someone, they've never fought someone like me."
O'Malley prepared for the fight by dying his hair the colours of the Ecuador flag but said it was "a sign of respect" rather than an attempt to "get in his head".
The main card includes former heavyweight champion Junior dos Santos of Brazil taking on Suriname's Jairzinho Rozenstruik. Both are ranked top six and train at the same gym in Florida, with different coaches.