British fighter Anthony Joshua survived the first knockdown of his young career, coming back to drop Wladimir Klitschko twice before stopping him in the 11th round to retain his world heavyweight boxing titles.

Before a boisterous crowd of 90,000 at Wembley Stadium, Joshua and Klitschko traded huge punches and showed grit before the local finally found a way to finish the longtime former champion.

It was anybody's fight when Joshua landed a right uppercut early in the 11th round that spun Klitschko's head around.

He was all over the Ukrainian and dropped him with a left hook, but Klitschko got up only to take even more punishment.

The 27-year-old Joshua knocked Klitschko down again and was landing punches to his head on the ropes when referee David Fields moved in to stop the bout late in the 11th round.

"A massive shout out to Wladimir Klitschko for taking part, I'm not going to say too much, in terms of the boxing hall of fame, he's a role model in and out of the ring," Joshua said.

"Boxing is about character, as I said from the get go it will be a boxing classic, find what you believe in and give it a go."

Joshua defended his heavyweight titles, winning for the 19th time in as many fights in a bout that lived up to its billing as the best heavyweight fight in more than a decade.