When it was put to Joshua that losing would not end his career, he replied: "One hundred percent and I know that it could happen because I know how tough this sport is".
Anthony Joshua delivers the knockout blow on Alexander Povetkin.
United Kingdom rapper Nines, meanwhile, performed a spin of his song "I see you shining" as the intro for Joshua to come out for his ring walk.
Povetkin, who has had two doping convictions, hauled himself off the canvas to halt the party, but his stay of execution was fleeting as Joshua charged back in to secure a 21st knockout in 22 professional fights.
Joshua's next fight will take place on April 13, again at Wembley Stadium, and an opponent is yet to be announced.
"Dillian deserves it more than Fury because he's been consistent and Wilder because he's the champion".
Joshua opened up the third round with a solid short right hand, but Povetkin was able to answer with an over the top right hand.
Povetkin had a cut open up by his left eye in the fourth round, and by the fifth round Joshua had landed 30 jabs to the 2 jab that Povetkin landed. Joshua landed a few good uppercuts and left hooks and likely took the round with his accurate punching.
"If you look close enough you can see Joshua shout 'this is for Salisbury spire!'"
Povetkin, who won Olympic gold in 2004, is the mandatory challenger for the WBA title - but all four of Joshua's divisional belts will also be on the line in London.
Povetkin remained risky with his left hook and overhand right, but Joshua increasingly gained control through his jab and in the sixth landed a short right hand from close range that the Russian did well to shrug off.
"This was about getting that big banana skin of Alexander Povetkin out the way".
But Povetkin could do nothing to repel the punches that rained down on him in the deciding seventh round. The fight will show everything.