Mark Tibbs believes Anthony Joshua is in for a hard night when he steps into the ring against WBO mandatory challenger Oleksandr Usyk.
AJ is making the second defence of his second reign as unified heavyweight champion at Tottenham Hotspur Stadium on Saturday night.
Both fighters have something in common - Olympic glory in London. Joshua won the super heavyweight class while Usyk topped the podium in the heavyweight category.
Usyk - who will have Anatoly Lomachenko in his corner - won the World Boxing Super Series in 2018 and in doing so became undisputed champion at 200lbs.
He went on to retire Tony Bellew before moving up to heavyweight and has beaten Chazz Witherspoon and Derek Chisora.
Should Usyk overcome Joshua, Usyk will be just the second fighter to conquer the cruiserweight division and then unify at heavyweight - after Evander Holyfield.
Joshua is the favourite to retain his titles but Tibbs - who is working with heavyweight prospect Johnny Fisher - is expecting the Londoner to be tested by 'special boxer' Usyk.
"I really think it's a tricky, difficult fight for AJ for sure. With Usyk's experience, he will know how to pack on that weight because I don't really see him as a fully-fledged heavyweight but I think he would have done his homework and he's super, super skilled and seasoned," Tibbs exclusively told Planet Sport.
"I'm looking forward to a very, very competitive fight. I can't pick a winner. I'll have to look and weigh up body language and get into the build-up before I make my mind up but Usyk's a very very special boxer and that's something he is born with.
"For me, AJ has been a great ambassador for British boxing and if I had to put my money on someone it would be AJ as the natural heavyweight and as a British fighter but I think he's going to be a problem Usyk - I hope not.
"That's what us 'boxing people' think that the bigger man will walk him down but when you get peppered all night in the face it's difficult," Tibbs added when asked if the fight would be determined by the later rounds.
"The trickery that he [Usyk] has in his armoury is going to make it a big fight for us fans to watch it's going to be intriguing."