Artur Betebiev has revealed the result of one amateur fight with Oleksandr Usyk.
Usyk is currently the unified heavyweight champion having beaten Anthony Joshua twice, and then Daniel Dubois last year in Poland.
He is now preparing to face Tyson Fury on February 17 to decide the status of the undisputed heavyweight champion - the first of the four-belt era.
Beterbiev is also a unified champion, operating at light heavyweight, and he fights British challenger Callum Smith at the weekend.
But in the past, Usyk - a former cruiserweight - was at the same weight as Beterbiev, and the pair met when they were coming up through the amateurs, though he did also lose to him twice, in 2011 at the amateur world championships and the 2012 Olympics.
"That time my weight was only 83kgs," he told Sky Sports.
"I've never been 90kgs in a fight.
"We had another fight too in the amateurs," he added.
"There was a match [in Russia], I had fight with him there at 81kgs and I beat him on the first day [of the tournament].
"You know Oleksandr Usyk, he does his job very well. What I can say, good for him."