Joshua puts his IBF, WBA and WBO heavyweight titles on the line when he faces the Russian at Wembley Stadium on September 22, live on Sky Sports Box Office.
Povetkin’s only defeat in 35 fights came against Wladimir Klitschko in 2013 and, while he is 11 years older than Joshua at 39, Khan believes his power can trouble AJ.
“Joshua had a few problems in his last fight against Joseph Parker. Povetkin is a very similar fighter to Parker but a lot better,” Khan told Sky Sports News.
“He has a lot more power, a great left hook and decent stamina. But the thing about him now is his age, whereas Joshua is looking amazing, knocking out whoever they put in front of him.
“He’s winning every fight, looking sharp, and is still young. I don’t think he’ll stop Povetkin, it’ll go the full distance, but it’s up to him if he makes it hard or easy.”
Khan climbed off the canvas to beat Samuel Vargas last weekend for the 33rd win of his professional career, and the 31-year-old reiterated his preference for a world title fight with Manny Pacquaio ahead of an all-British battle with Kell Brook.
“It has to be Manny Pacquaio, that’s my first choice because he is coming to the end of his career,” said Khan.
“How much of Manny Pacquaio do we have left? Kell Brook is more or less the same age as me, there’s only six months age difference. He’s still going to be around.
“To have someone like Pacquaio on your resume would be massive. To say I beat Pacquaio, who is an eight or nine-time world champion, would be amazing.
“My first option would be Pacquaio. He also holds a world title as well, whereas the Brook fight isn’t for a world title.
“Hopefully we get past Pacquaio, we win that fight. That puts the Kell Brook fight right there for us.”
While Pacquaio is nearing the end of his boxing career, Khan has no intention on hanging up the gloves just yet.
“If I lost another fight there may be some thinking over retirement but it just depends on how your body feels,” he said.
“It just depends on yourself really and what you want from the sport.
“I’m not doing it for the finances. I’m doing it because I still love the sport and have a lot more to show the world.
“Time will tell, and I’ll be the first to know. I never want boxing to retire me, I’d rather walk away before it does that.”