LONDON - Former world champion Anthony Joshua needed seven rounds to stop stand-in opponent Robert Helenius in their heavyweight bout on Saturday.
Joshua, 33, looked ponderous in the early stages and the British boxer was jeered by his London home crowd. But he finished the fight with a thunderous knockout of Finland's Helenius at the O2 Arena.
Victory kept Joshua on course for a bout with fellow former world heavyweight champion Deontay Wilder.
"People need to leave me alone, this is my time in the ring," Joshua told DAZN.
"Let me keep doing what I want to do. Helenius, I told him to come again. I think he can cause people a lot of problems."
As for a bout with Wilder, twice world champion Joshua joked: "My back's gone, is there a doctor in here? I want to carry this heavyweight division to the top!"
Helenius was only drafted in after fighting in Finland last weekend when Dillian Whyte was ruled out of what would have been an all-British clash following "adverse analytical findings" in a doping test.
The 39-year-old Helenius, who entered the ring with 32 wins and four defeats from his 36 professional bouts, was knocked out in the first round by Wilder in October.
He avoided a repeat of that embarrassing reverse on Saturday although, with Joshua making a cautious start, boos rang out from a capacity crowd during the third round.
Joshua, however, landed with a left hook and then hit Helenius with a right to the face later in the round.
The local hero rocked Helenius again in the fourth before the veteran caught Joshua with a jab.
But the fifth round left Helenius with a bloodied nose and although Joshua made him stumble with a left uppercut, he survived and got through an uneventful sixth round.
Joshua did give his fans what they came to see when he knocked out Helenius with a powerful right-hand punch in the seventh.
Helenius briefly remained motionless but eventually got back to his feet before touching gloves with Joshua as a mark of respect.