Anthony Joshua says he tried to outbox Oleksandr Usyk during their heavyweight title fight last year to prove he was not just a “big stiff body-builder”.
The taunt is often aimed at him by heavyweight rival Tyson Fury.
Joshua, 32, lost his WBA, IBF and WBO heavyweight belts when Usyk won by unanimous decision in September.
“Usyk came up from cruiserweight, he is a great fighter, a 12-round fighter, and I wanted to box with him for 12 rounds,” Joshua told Sky Sports.
“There was always this stigma that I can’t box, that I was this ‘big stiff body-builder’.
“So I said ‘cool, let me practise my boxing’. I tried practising my boxing with Usyk. He won nine rounds, I won three.
“Next fight, I win four more rounds – I win. So, let me simplify that matter, and I’ll then get on the road to being undisputed champion.”
Defeat by Usyk dashed Joshua’s immediate hopes of a unification bout with Fury, who won his trilogy bout with Deontay Wilder in October to retain his WBC belt.
Joshua’s promoter Eddie Hearn has triggered a rematch clause against the Ukrainian, while British rival Dillian Whyte has been named as Fury’s mandatory challenger by the World Boxing Council.