LONDON (AP) — Anthony Joshua was walking back to his dressing room, dazed, bedraggled — he could barely see out of his right eye — with sympathetic shouts coming from the crowd of 66,000 who’d just seen British boxing’s national treasure lose his world heavyweight titles again.

Joshua was trying hard not to feel sorry for himself. In fact, he was already plotting how he could defeat Oleksandr Usyk in a rematch.

“When I was walking back through the tunnel, I just said to myself, ‘I’m ready to get back to the gym, I’m ready to just put that work in,'” Joshua said. “Most people after they’ve finished a fight, it’s like, ‘Yeah, let me go out and have a bit of fun.’ But my mindset is a bit different.”

So, after shaking hands with Usyk and video-calling the new champ’s kids back in Ukraine, Joshua got his team to put on a tape of the fight and watched it with two people close to him — Tony Bellew and Derek Chisora — who have also lost to Usyk over the past three years.

“This isn’t just one fight and then I’m done,” Joshua said. “I’ve got an opportunity to go back to the drawing board.”

The video will have been a tough watch. Befuddled by fighting a southpaw for only the second time, Joshua was given a lesson in movement and punching speed by an undefeated 34-year-old opponent who demolished allcomers in the cruiserweight division and — after just three fights at heavyweight — already owns three of the four major belts in boxing’s blue riband category.

To Joshua’s promoter, Eddie Hearn, Usyk is the second best pound-for-pound fighter in boxing.

“Anthony could have swerved that fight easy. Maybe we should have,” Hearn said. “But that’s not really what he’s about.

“You’ve got people who will take easy options and you’ve got people who will choose to fight everybody. And the latter is AJ.”

So, Joshua will “100%, 110%” trigger the rematch clause that was part of the deal.

Hearn said it will take place in February or March, hopefully in Britain and almost certainly not in Kiev – the preferred location for Usyk despite his fearsome reputation as a road fighter.

Joshua’s coach, Rob McCracken, think he knows how his man can close the gap on Usyk and avoid getting in the kind of situation that saw him hanging on the ropes by the end of Saturday’s fight, on the end of a pummeling in his own back yard. He surely would have gone down had the final bell not sounded.

“You’ve got to apply pressure behind your jab and your right hand, keep him off-balance and put your shots together when you get there,” McCracken said.

Easier said than done.

Usyk will start as favorite in the rematch — Hearn said that, and Joshua didn’t disagree — and is blessed with such talent and pedigree that he’ll be confident of outboxing his fellow Olympic gold medalist from 2012 once again.

It was some performance, in only his third heavyweight fight, in such a fevered atmosphere and against a two-time world champion. By the end, he was bullying the younger Joshua — a man with a distinct advantage in height, weight and reach – and won comprehensively on all three of the judges’ scorecards.

“It is the biggest fight in my career but it wasn’t the hardest one. That is ahead of us,” Usyk said.