It took Anthony Joshua a while but he delivered in the end.

The former heavyweight champ spent half the fight trying to figure out how he was going to land a bomb on Robert Helenius but finally did in Round 7, a single right hand that ended the fight instantaneously Saturday at O2 Arena in London.

The victory is his second in a row after devastating back-to-back losses to Oleksandr Usyk and sets up a showdown with fellow former titleholder Deontay Wilder.

"That's the fight we want," said promoter Eddie Hearn, referring to Wilder. "We have a three-fight plan, whether you like it or not. It was Robert Helenius, supposed to be Dillian Whyte; Deontay Wilder, and then Tyson Fury.

"That's the ambition of the team."

Helenius, who stopped a journeyman in three rounds last weekend, took the fight with Joshua on less than a week's notice after Dillian Whyte failed a drug test and was pulled from the card.

However, he performed reasonably well … for a while.

Joshua (26-3, 23 KOs) controlled the fight with his jab and threw power shots here and there but was reluctant to take significant risks as he tried to figure out his opponent, instead waiting for the perfect opportunity to land a big blow.

The lack of action drew boos from the hometown fans, who obviously wanted Joshua to attack with more ferocity.

Then everything changed in a breathtaking moment. Helenius had his back against the ropes when Joshua unleashed a straight right hand that caught Helenius on his chin, sending him to the canvas in an unconscious state and lifting the suddenly satisfied spectators to their feet.

Referee Victor Loughlin had no need to count as it was clear that Helenius couldn't continue. The official time of the stoppage: 1:27.

Just like that Joshua, fighting for the second time with new trainer Derrick James, turned what had been an uninspiring performance into a Knockout of the Year candidate. That's exactly what he hoped to do going into an expected meeting with Wilder late this year or early in 2024.

"He's got talent," Joshua said about Helenius. "So I had to figure him out. He was a late replacement. And I think he can cause a lot of people some problems, in my opinion. Credit to him for coming out tonight and saving the show. … I need to stay busy. I need to keep on building, keep on building. I've been off for too long."

Joshua had no inclination before Saturday to discuss a prospective meeting with Wilder.

He was asked again about what would be one of the biggest possible heavyweight matchups. He didn't answer the question directly but made it clear by play acting that he's on board with a heavyweight takeover.

"My back, my back. Is there a doctor in here? My back is going," he said, his voice rising, "… [is going] to carry this heavyweight division to the top."

Hearn clearly believes in his longtime client, a 33-year-old former two-time heavyweight champion bent on a third reign.

"Whether you back Joshua, whether you think he can do it, whether you think not, he's changed," Hearn said. "He's now a mature heavyweight. I know everyone wants to see a first, second, third round KO, but against Helenius he took his time and delivered one of the knockouts of the year.

"And we believe he can go on to beat Deontay Wilder. … We look to try to close that deal over the next couple of days. Joshua is ready for that fight."