I thought he lost his first fight with Tarver. The Roy Jones fans will say it was going up to Heavyweight and coming back down that affected him and caused him to lose. I think it was more how quickly he came back down to Light Heavyweight. If he'd gradually come back down over say 18 months, rather than 6 months, I think he would have been ok.
Hopkins lost his very first pro fight, then took 18 months out. 3 years later he fought Roy Jones when he was still very green and not ready for Jones.
If we are talking about boxers who have been most affected by their first loss I'd have to go for Meldrick Taylor or Jeff Lacy. Both were never the same again.
Most affected is Naseem Hamed who quit boxing cold turkey after losing for the first and only time to Marco Antonio Barrera.
Least affected are Juan Manuel Marquez and Bernard Hopkins who lost their very fights by DQ and MD respectively. Both are now on the verge of attaining ATG status if not already certified ATGs.
Many fighters are and have been very affected by their first loss. Meldrick Taylor and more recently Juan Manuel Lopez are recent examples. A past example is Billy Green; he was 35 wins 35 knock outs 0 draws 0 losses but after his first loss he just kept loosing and only beat nobodies [with Lamotta being the only exception].
Some fighters aren't very affected by their first loss. Great names include Harry Greb, who lost his 4rth pro fight and got knocked out [for the only time in his career] in his 7th pro fight. Greb went on to win over 270 pro fights and became 1 of if not the greatest middleweight ever.
Henry Armstrong, commonly cited as the greatest if not top 5 greatest p4p ever, lost 3 of his first 4 pro fights, and his first pro fight was via 3rd round ko [again, the only time he got knocked out cold in his pro career]. Imagine if Armstrong had retired after those first 3 losses, like many would do?
Already a lot of good ones mentioned.
Juan Manuel Lopez has been horrible ever since his first KO loss.
There's a guy named Tim Coleman, who was a good prospect and then got knocked out by Vernon Paris. After that he got stopped in his next two fights, both in under two rounds.
Acelino Freitas was the man at lightweight, then he got knocked out by Diego Corrales for his first loss. After that he looked okay against easy competition for a couple of fights, then struggled badly against Zahir Raheem, then quit on his stool against Juan Diaz.
Naseem Hamed had one fight after the MAB loss, then retired. I don't know if there are different issues there, but Hamed was a confident fighter and MAB seemed to really take the wind out of his sails.
A lot of guys rebound off losses well, like Cotto, B-Hop, JMM, Pac, Sergio Martinez, Vitali Klitschko, etc....that happens more often than a loss ruining a fighter.
Seeing as Jeff Lacy has already been said, I will go with Lucian Bute. The manner in which he suffered it too means he will never be the same again. Since then he's 1-1 and the fight he did win wasn't the best of displays either
Bernard Hopkins lost his pro debut ,at that point ,who would have ever guessed that 0-1 Bernard Hopkins would have went on to win a middleweight title ,with 19 straight defenses ,on to becoming an ATG.
Gerard McClellan after his first lost to Nigel Benn, brain damage.
Khan's lost to Prescott, KO R1.
Foreman
For example, Roy Jones Jr, after his 1st loss (not including the disqualification) ended up losing 3 in a row and has never gone on to win 4 in a row since.
Bernard Hopkins,lost his first fight and went on to win 22 and after his second loss went on to win 24.
