Andy Lee believes mental toughness would see his fighter Tyson Fury overcome Anthony Joshua if they meet in a world title unification bout.
Promoter Eddie Hearn has suggested that a deal could be struck for an all-British clash between the pair to unify the heavyweight division later this year.
Having helped Fury prepare for his WBC title win over Deontay Wilder earlier this year, Lee is no doubt about who would win if the 31-year-old faces Joshua.
"I think Joshua still an improving fighter," the former middleweight world champion told Sky Sports News. "I think he showed huge improvement to beat Andy Ruiz.
"I think a little bit of inexperience, and I think mentally, he's not as strong as Tyson. Emmanuel always said, champions are built on the inside.
"I think Tyson would beat him in eight rounds. I like Anthony Joshua, I think he's a great fighter, and a great champion, but I think he's a little bit inexperienced for years of fighting.
"I still think it's a great fight, and a great match-up. It's the only real match-up in the heavyweight division left for both guys, but I think Tyson wins in a similar fashion to what he did to Wilder."