Bellator star Ryan Bader says he wants to avenge his loss to Jon Jones -- the guy he calls the GREATEST MMA fighter ever -- 'cause he's got what it takes to beat Bones' ass.
TMZ Sports talked to the Light Heavyweight and Heavyweight champ at a Bellator media event in NYC this week ... and the 36-year-old star says he'd LOVE another crack at fighting Jones.
"That's one fight I'd love to get back," Bader tells us.
"It was 2011 when that happened. I've grown and changed so much since then. Physically, mentally. We'd love to be able to do some cross-promotion deal."
Remember, Jones submitted Bader via a guillotine choke at UFC 126 in February 2011. It was Bader's first loss of his career.
Fast forward to current day ... RB's a double champ, and hasn't taken an L since 2016.
So, Ryan's got revenge on his mind ... and he's dead serious about getting payback.
"If we can make some sort of cross-promotion [between Bellator and UFC], exhibition, whatever the hell it is. Just unify [the LHW title]."