Upon conceding a split decision in the fight in Jeddah, a furious Joshua stalked towards the changing room before returning to the ring, grabbing Usyk's WBA and Ring Magazine belts and dropping them outside the ropes.
He then confronted Usyk, saying "you're not strong, how did you beat me? How? I had character and determination", before addressing the crowd with a confused rant about his past and his own shortcomings as a boxer.
"What you saw was raw emotion. A real person who was feeling the pressure and who wanted to win so badly," said promoter Eddie Hearn as he addressed the negativity that has stalked Joshua's career.
"You live in an online world where it's opinion, stick, abuse. He will never tell you that he sees that pressure or feels it, but it's impossible not to.
"I just want AJ to be happy. He's given his whole life since he started boxing and people don't realise what a bubble it is.
"Everybody in the country knows who he is. Everyone has got an opinion on who he is. He's in the gym all the time with his team.
"There isn't anyone I know who is more dedicated to the sport than him and sometimes people don't understand the pressures that are on people's shoulder. But he's never ducked a challenge.
"You see these complete d********, many of them on social media, they've got too much to say for themselves.
"They want to pretend they are good people when AJ is someone I want my kids to look up to. That responsibility is a huge burden and AJ's always felt it."