WBC heavyweight champion Tyson Fury is still hopeful that he can finalize an undisputed fight with Oleksandr Usyk - but he's far from confident that a future clash can be made with domestic rival Anthony Joshua.

Earlier this year, Fury and Usyk were in serious discussions, but they were unable to reach an agreement on the financial terms for a rematch.

"We don't really know the reasons why Usyk didn't take the fight in April," Fury told Sky Sports. "I'm sure he's got his reasons and then we find out he's signed with Skills Challenge, the Saudi Arabian team of boxing people out there. So whatever his reasons are, I'm sure that they suit him and his family. It is what it is.

"But I do believe that you can only do what you can do in this sport. If the fights are available at that time then you take them and if they're not available then you can't take them. Will we fight in the future? Hopefully. I'd like to. I've always believed it's an easy fight."

Usyk returns to the ring later this month in Poland, in a mandatory fight against Daniel Dubois.

Joshua is back in action this coming weekend, against late replacement Robert Helenius.

Should Joshua win, he would then move forward with a potential clash with Deontay Wilder on a date in January in the Middle East.

"In this last year I've tried two or three times. It's always not happened for whatever reason. I'm not optimistic. For about a week during the negotiations of this year I was very optimistic," Fury said.

"I thought for years and years that me and Joshua would have fought each other. And he's not been wanting to take that challenge for years. So you can't force somebody to do something, no matter how much money there is or how many belts there are or whatever there is on the line.

"You can't force someone to do something they don't want to do. Unless both parties are willing then these fights don't get made, as we've seen over the years."

To stay busy, Fury will enter the ring on October 28, in a crossover boxing match with former UFC heavyweight champion Francis Ngannou in Saudi Arabia.