In a much-anticipated rematch of their bruising 11-round classic earlier this year, Dubois dominated Wardley from the opening bell to batter his rival into submission in the second round.
Dubois dropped Wardley after 17 seconds of the contest at the O2 Arena in London, catching the challenger flush on the chin with a huge overhand right.
The 29-year-old Dubois continued to land punches at will throughout the first round, which finished with Wardley clinging on desperately under a barrage of punches on the ropes.
The second round started as the first had ended, with the 6ft 5in Dubois uncorking an array of punches that left Wardley in desperate trouble.
With Dubois unloading on a defenceless Wardley, the towel came in after two minutes and 21 seconds of the round.
Dubois improved to 24-3-0 with 23 knockouts, while the 31-year-old Wardley fell to 20-2-1.