A stunning left hook in the seventh round left Povetkin visibly shaken, and Joshua smelled blood.
Povetkin struggled to his feet but Joshua finished him with a brutal right hand that sent him to the deck again as the fight was being waved off.
The Brixton fighter appears the most likely opponent for the April contest in London but should Wilder negotiate past Fury, it becomes a fight with enormous significance in the heavyweight division.
'I'm not in the blame game, ' Joshua said when asked why previous negotiations with Wilder collapsed. "Povetkin is a very tough challenger. I feel like this is home".
The then-raw professional was monitoring Klitschko's career, and discussing the way he and Povetkin have since been brought together, he said: "It's insane".
The fight between WBC world heavyweight champion Deontay Wilder and Tyson Fury will take place on Saturday, 1 December.
"It's a very comfortable and good weight for me, I feel great", he said, via a translator.
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Meghan gave a heartfelt speech in which she said she felt "privileged" to know the women of the Hubb Community Kitchen . Markle also penned the book's foreword, in which she discussed the importance of the kitchen to the Grenfell community.
Despite the sizeable weight advantage, unified champion Joshua insists he is agile enough to bring up his 22nd professional victory. "My No. 1 would be Wilder".
The Englishman was heavily favoured to do the business, in front of his home fans at a soggy Wembley Stadium on Sunday morning (NZ time), and the 28-year-old proceeded to maintain his flawless professional fight record (now 22-0) in keeping his WBO, IBF and WBA belts safe.
Hearn added: "If it's not Wilder, Whyte would be next. If it's not Deontay Wilder then it will be Dillian Whyte on April 13".
'The sport is about what the fans want, let's put a poll out on Twitter and see who fans want me to take on'.
(Joshua's) not an Instagram champion he's a proper champion.
Povetkin got tagged with several good jabs by Joshua in the sixth round. It's lining up for April 13.
Povetkin, 39, knew this was most likely his last shot after being floored four times in a unanimous points loss to Wladimir Klitschko five years ago.