Easily it has to be Tito. Trinidad beat him down when he still felt he had a chin that was unbreakable. He had lost that aura by the time he fought Oscar.

Example: Tito brutally KO's Vargas and Vargas in turn comes out gets dropped in his very next fight against an old Wilfredo Rivera. People don't come back the same after beatings like that and so many hard punches on the chin.

Remeber that's the same Oscar who couldn't put away little Stevie Forbes so let's not get carried away.