Dejesus was not extremely capable when hefought Mamby. he looked awful imo and was sloppy as hell.Every inch a washed up drug addled fighter.
Put later 70s-very early 80s Mamby up against anyone ever at 140 and you get one of three results: 1) Mamby wins 2) Mamby loses a fairly close decision (and this would only be to the very best fighters) 3) Mamby loses by a total robbery decision
He was 35 and had fought for 13 years at that point. Likely past his prime by then. Althuogh he wasn't really totally over the hill enough to no longer be competitive against top fighters until around 43. The only real beating he took was against Billy Costello.