George Groves has been accused of boxing naively during his knockout defeat against super-middleweight world champion Carl Froch on Saturday.
The challenger's hopes of taking the IBF and WBA belts were ended when Froch floored him with a stunning right hand, but his former trainer Adam Booth suggested that he had been guilty of a silly mistake during the fight.
He told BBC Sport: "George opened his arm out for the left hook. It is something we talked about from day one but if you make a mistake like that then you will lose. I could see from the first round that Carl was sweeping that left hook across. He was doing that to keep George occupied.
"You cannot be naive against a guy like Carl Froch. Underestimate at your peril because he is a tough old man that is a lot smarter than his style and age shows.
"He has to go back and lick his wounds for a while and look at what he did wrong. He has to rebuild but he is young enough and wise enough."
Groves and Booth parted company in the build-up to the first fight in Manchester late last year.