The 27-year-old dominated the opening stages of the bout, dropping the two-time former unified heavyweight champion multiple times.
In a dramatic fifth round Dubois was momentarily stunned by two right hands and just as Joshua looked to pile on the pressure, the 34-year-old was caught by successive right hands himself and he was down again, this time unable to beat the count.
“Are you not entertained?” Dubois said to huge cheers at Wembley.
“I’m a gladiator. I am a warrior to the bitter end. I want to get to the top level of this sport and reach my potential.”
Ukraine’s Oleksandr Usyk became boxing’s first four-belt undisputed heavyweight champion in May when he beat Tyson Fury, simultaneously holding the IBF title along with the WBO, WBC and WBA.
The Ukrainian agreed to a rematch with Fury rather than facing mandatory IBF challenger Dubois.
Dubois won the interim IBF title in June and was elevated to world champion status when Usyk vacated the belt.(AFP)
