Anthony Joshua is confident he can knockout any heavyweight on the planet after halting the division's long-time ruler Wladimir Klitschko in a Wembley thriller.

Joshua moved to 19-0 as professional, adding the vacant WBA and more lightly regarded IBO belts to his IBF crown, and appeared set for a typically quick nights' work when he sent his 41-year-old opponent to the canvas in round five.

But Klitschko, boxing for the first time since losing all those titles and the WBO prize in an upset defeat to Tyson Fury 18 months ago, fired back sensationally to leave Joshua hanging on as the session closed.

The 27-year-old was floored for the first time in his professional career in the next stanza by a crisp Klitschko right to the temple.

Joshua took time to regroup before a final assault launched by a devastating uppercut in round 11, with Klitschko subsequently going to ground twice and being stopped on his feet.

Speaking at a post-fight news conference, the 2012 Olympic champion conceded some fundamental lessons had been learned, while he enjoyed confirmation that he can maintain his thunderous power into the championship rounds.

"I learned that I can knockout anyone, no problem," he said before breaking into an infectious chuckle.

"I always say that I'm not the best at everything but, what I am good at, I'll do to my best.

"If I keep on improving on these little things that I do well then I think I can definitely knockout anyone, hurt any opponent."

Joshua added: "You've got to be smart in this game – this is a 12-round fight, not an amateur fight.

"I tried to take him out [in round five]. When I've hurt someone, I know I can get them. So I was searching – 'voom, voom' and [the punches] were just skimming his face.

"It does take a lot of energy out of you to hit someone hard and hurt them. I just was trying to connect too eagerly and I used a lot of energy.

"What I did then was try to recover so I could step up the gas again in the later rounds. That kind of became the gameplan in my mind."

Promoter Eddie Hearn reported pay-per-view buys for Joshua v Klitschko had smashed UK box office records and he expects his prized asset to be out again before the end of the year, possibly in October.

WBC champion Deontay Wilder was ringside and would be a mouthwatering option, although Joshua does have an IBF mandatory obligation to Bulgaria's Kubrat Pulev.

Trainer Robert McCracken was not overly swayed by the prospect of a Klitschko rematch given the comprehensive nature of his fighter's stoppage, although Joshua would be seemingly happy to honour such a clause.

"Maybe against anyone else in the division he would have come out on top," he said.

"I have the ultimate respect for him and what he's achieved inside and outside of the ring, but I wouldn't mind fighting him again if he wants the rematch, no problem."