Roy Jones Jr is confident he and Mike Tyson would have beaten Anthony Joshua and Tyson Fury in their heyday.
The faded legends are preparing for their eight-round exhibition fight on September 12 after agreeing to a bizarre set of rules.
There will be no ringside judges in California and the referee will be allowed to stop the fight if either man is hurt or cut.
Jones, 51, and Tyson, 54, hope fans in America will stump up $50 to watch the farce which will be held behind closed doors due to the coronavirus crisis.
And as he continued his promotional tour, Jones claimed he backed himself to pick off current world champions Fury and Joshua.
"Not right now [we wouldn't beat them]; it would be hard for us to last twelve rounds with any of those guys," he told Sky Sports.
"They are skilled fighters, not bad boxers. They are not as skilled as we were but they are in their primes, and we are not.
"In our primes? We would probably have beaten them. You can never say, but I think we would probably have beaten them.
"Our skill level was deeper, at that time, than it is now. In our prime we would have come out on top against most of those guys.
"But you never know because it never happened so you can't discredit those guys. They are good fighters, well-respected fighters, and my hat is off to them because they are at the top."
Tyson has been flirting with a comeback for several months after posting footage of himself in training.
He was linked with several opponents, including former bitter rival Evander Holyfield, but eventually plumped for Jones who retired in 2018.
