Joshua's attempt to reclaim the title as a three-time world champion ended in a disappointing manner when he was knocked down four times and ultimately faced a fifth-round knockout against IBF champion Dubois at Wembley Stadium, where 98,000 fans were in attendance.
“In my humble opinion, he is done, and he should explore investment opportunities,” Zhang remarked to DAZN via AceOdds.
“He ought to think about retirement and focus on the business aspects of his life. Whatever path he chooses, he should pursue it.”
Despite his critical view of Joshua's career trajectory, the Chinese boxer, who last fought in June and achieved a significant knockout victory over Deontay Wilder, expressed a desire to face Joshua in the ring.
“Despite everything that has been said, I would like to fight him, but I doubt he is interested in facing me. I also don’t believe Eddie Hearn will allow him to fight me,” Zhang noted.
Zhang's call for Joshua to retire follows advice from former undisputed heavyweight champion Lennox Lewis, who recommended that Joshua take a break from boxing after the heavy defeat.
“No, I don’t think he should pursue a rematch. He should take some time off and then return,” Lewis stated to Box Nation.
The British boxing icon believes that Joshua reached his peak during his victory over Wladimir Klitschko in 2017.