Otto Wallin insists Oleksandr Usyk can be beaten after being forced to 'dig deep' in his rematch against Anthony Joshua in Saudi Arabia last week.

The 35-year-old from Ukraine staged a fine comeback to beat Britain's Joshua on points despite trailing on all three scorecards after nine rounds at the Superdome in Jeddah.

Usyk, 35, defeated Joshua, 32, for the second time last weekend to retain his WBA, WBO and IBF heavyweight titles, picking up the Ring Magazine belt in the process.

However, Wallin believes he lost his aura of invincibility, as he insisted that he showed some vulnerabilities.

JUST IN: Frank Warren believes Oleksandr Usyk would lose to Tyson Fury and Joe Joyce

Wallin told OLBG: "It was a great fight, and both guys stepped it up from last time. I was actually impressed with Joshua’s adjustments for this fight.

"I didn’t think he was going to be able to put up such a good performance against Usyk, but he proved me and I’m sure a lot of other people wrong.

"Usyk really had to dig deep, and he once again showed that he’s a brilliant fighter, but we also saw that no one is untouchable."

Oleksandr Usyk beat Anthony Joshua on points

Much has been made of AJ's reaction to losing to Usyk after footage emerged of him throwing two of the belts out of the ring.

Wallin, 31, admitted that he fears for Joshua's mental wellbeing and that it was something he took no pleasure in seeing.

He added: "It was hard to watch [Joshua post-fight] to be honest.

"I think it’s a culmination of pressure on him and I think that it’s affecting him a lot mentally.

"He did a similar thing when he lost to Ruiz and took the mic from him. It’s like he’s so used to being the champion, so it’s hard when he’s not that anymore."

READ MORE: Tyson Fury vs Oleksandr Usyk: Eddie Hearn sends firm warning to the Gypsy King on potential clash

But Wallin also wouldn't mind being Joshua's next opponent when he returns to the ring.

He continued: "I think it makes a lot of sense for me and Joshua to fight each other. 

"People in the UK know me for giving Fury one of his toughest fights in his career and I get a lot of support from over there. 

"I’m always training and trying to get better and I can’t wait to go over to the UK and earn my right for another shot at Fury by beating Anthony Joshua."