Hours after he was disrobed of his IBF, WBA and WBO belts by Oleksandr Usyk, the former heavyweight champion, Anthony Joshua says he remains upbeat despite the defeat.

The two-time former unified world heavyweight champion broke his silence in a tweet in the early hours of Sunday.

The world watched in disbelief as Joshua lost all his belts to the Ukrainian on Saturday night in front of 67,000 fans at the Tottenham Hotspur Stadium.

The fight was adjudged 117-112, 116-112, 115-113 for Usyk.

AJ, as the British boxer is fondly called, tweeted “Keep positive even if the world’s crumbling in front of you! London I love you & thank you each and every time!”

With his victory, Usyk became one of only three boxers to have unified the cruiserweight world titles and become a world heavyweight champion, joining Evander Holyfield and David Haye.

He also became the second boxer, after Holyfield, to unify both cruiserweight and heavyweight titles.