Lennox Lewis ain't been the heavyweight champ in 16 years ... but the boxing legend tells TMZ Sports he could step into a ring right now and beat up some the best fighters in the world.
We were talking to the 3x heavyweight champion and boxing Hall of Famer about Deontay Wilder (Lewis' calling DW's fight vs. Luis Ortiz Saturday night) ... when the British star hit us with a doozy, saying his 54-year-old body could STILL whoop-ass in the ring.
"Even right now, I'd give a lot of guys a run for their money right now," Lewis says.