Right off the top of my head I will say David Reid after getting a thorough beat down from Tito... Perhaps Vargas too, after falling victim to Felix? Alfonso Zamora also comes to mind, after his defeat to Carlos Zarate. Prince Hamed simply was so outclassed that he pretty much decided to retire right then and there. What about Michael Nunn after Toney? I'm sure there are many more examples of fighters who took one particular defeat so badly, that any subsequent showings by them allowed us to see that they were not "the same" they used to be. By "the same" I mean not having as much confidence as before... that solid self assurance they used to have and that is of prime import if one is going to face someone as skilled or more than onself in, of all places, a boxing ring. Perhaps Roy's loss to Tarver could be counted... although a case could be made that Roy wasn't even at his best when they fought for the first time, right after the Ruiz match. Not to jinx the bout but... will Pretty Void be ever the same if Hatton knocks him out? How will Ricky take the loss if he is clowned to death by Mayweather? Will they be the same?:verysad
Brewster after Liakhovich, he really took alot of punishment in that fight, he also gave alot to Liakhovich as well. When he fought Wlad it was easy to see he was only a shell of his former self, it was sad sight IMO.
The biggest has got to be Donald Curry after Honeygann.. just because based on pedigree...crazy Amatuer career.. and unbelivable style Curry could have been knockin on SRR and ALis door
Actually Vitali after Byrd fight. He didn't take no punishment, but he become much much worse. His big bad KO artist image was gone and he became robotic with all those other injuries too. He used to be actually pretty mobile. Even in Byrd fight he is much more mobile Andrey