On Saturday night in Poland, heavyweight contender Daniel Dubois will challenge WBO, IBF, IBO, WBA world champion Oleksandr Usyk.

The contest will be the first for Dubois with new head trainer Don Charles.

Earlier this year, he parted ways with trainer Shane McGuigan.

In breaking down the upcoming fight of his former charge, McGuigan explained that Dubois has to be aggressive and firing with both hands.

"Dubois has to approach this fight like a four-round contest, like Mike Tyson used to approach most of his fights. If it goes past four rounds then we have to find out what plan B is about and learn to get through it," McGuigan told BBC Sport.

"But they have to have the mindset 'If I clip or touch you, you're going to sleep' - so you have to let your hands go in combinations, not let them set on the jab, and really stick it on Usyk. He's definitely got a puncher's chance, for sure."

Former world lightweight champion Anthony Crolla, who now trains fighters, believes Dubois has to land early to give himself any chance of victory by securing Usyk's respect.

"You have to give Dubois a puncher's chance but it's probably hard to look past any more than that. Going on recent form, Usyk has been looking really good and Dubois struggled last time out against Kevin Lerena," Crolla said.

"The movement is going to be a big problem. If Dubois is to pull off a big upset, which is exactly what it will be, he has to land early to get the respect off Usyk. I believe Dubois is a confidence fighter - he has to have a good start to have any chance of winning it."