The Brit was originally scheduled to fight his compatriot Dillian Whyte, who failed a doping test and was replaced by Finn Robert Helenius, who agreed to take the fight on short notice.
After a cautious and comfortable six rounds from Joshua, midway through the seventh three minutes the former world champion managed to land a crushing right jab that sent Helenius to a knockout and set the stage for this match.
Thus, 33-year-old Anthony Joshua wins his second consecutive victory after losing twice in title challenges to Ukrainian Oleksandr Usik, who took the WBA Super, WBO, IBF and IBO heavyweight titles away from the Briton.