Former two-time heavyweight champion Anthony Joshua believes division rival Deontay Wilder lacked a proper game plan for last month's trilogy fight with WBC world champion Tyson Fury.
In one of the best heavyweight fights in recent years, Wilder was dropped hard in the third - but then scored two knockdowns on his own in the following round. Fury would rally back and drop Wilder two more times for a knockout in the eleventh.
Joshua gives Wilder some credit for giving it a go, but felt the wrong tactics were used.
"He tried, but to get that power and that ferociousness, you have to have it up here [points to his head]," Joshua told a JD Sports roundtable.
"Before you have it just here [clenches fists] at that level, you have to have it here [points to his head] as well."
Wilder was doing a lot more jabbing than previously seen in the second encounter.
Joshua explains why an effective jab, in the modern era, is not enough to be a dominant force in the heavyweight division.
"Not in this day and age [can a heavyweight just jab his way to win] because heavyweights are different. I met the guy who makes gloves the other day, and he said that they never used to have to make special gloves. But now heavyweights are 17 to 19 stone and six-foot ten. The whole division is changed in the last, like, five years," Joshua said.
"And before, fighters could jab like that for twelve rounds and get away with it. They'd get a bit tired, but they were conditioned because they were lighter. But now, when you've got big guys [who are] six-foot-seven, they get tired."
Joshua was shocked back in September, when Oleksandr Usyk outboxed him over twelve rounds.
He will attempt to reclaim his WBO, WBA, IBF, IBO titles in the first quarter of next year, when he faces Usyk in a rematch.
The British star is aiming to bring back the fighter who retired Wladimir Klitschko in 2017.
"I'm gonna bring that energy back. But I'm not gonna go into my training and all that," Joshua said.