I once watched a very good documentary on the career of Wilfredo Gomez, up to and including the Salvador Sanchez fight. Gomez was a beast at super bantam... probably the best there ever was. But he went up to featherweight and immediately met probably one of the greatest featherweights in history (probably would've ended up being the best ever, but tragically died young). I'm pretty sure Gomez underestimated Sanchez. He wanted the rematch badly, but it never happened as Sanchez died in a traffic accident.