Gennadiy Golovkin has been warned underdog Sergiy Derevyanchenko is "a major force" before their world middleweight title fight.
The pair went face-to-face at a press conference on Wednesday before they contest the vacant IBF belt on Saturday night at 2am, with the bout live on Sky Sports Action.
"If you like a real fight, please don't miss this," Golovkin said after his opponent had made clear his intention to cause a major shock.
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Derevyanchenko's promoter Lou DiBella said: "As great as I think [Golovkin] is, one of the greatest things to come out of Eastern Europe, all good things have to come to an end."
His manager Keith Connolly warned: "You don't have 410 amateur fights, and win 390, and not have a chance to win the middleweight title."
Derevyanchenko's trainer Andre Rozier added: "We have a major force, and it will truly difficult for [Golovkin] to overcome."
Derevyanchenko concluded: "Saturday night, I am ready to rock and roll."
Golovkin has never been on the floor in a combined 391 amateur and pro fights, and lost for the only time in his 41-fight career when he was controversially outpointed by Saul 'Canelo' Alvarez last year.
The 37-year-old plans to regain a world title this weekend in his first fight working with promoter Eddie Hearn.
Derevyanchenko, a former Olympic team-mate of Vasiliy Lomachenko and Oleksandr Usyk, has lost just once in 14 fights - a split decision against Danny Jacobs.
Johnathon Banks, who is training Golovkin for just their second fight together, promised: "It will be a competitive, a tooth and nail type of fight."
The middleweights went head-to-head and will meet again at Friday's weigh-in.