Mayweather at 130 was a special fighter, but he never fought anyone anywhere near as good as Arguello or Chavez, so I find it difficult to therefore say he was 'invincible' as we simply do not know how he would have fared against truly great opposition. Personally, I think Arguello beats Mayweather in a 15-round fight at 130. I think Chavez gives him a great fight. So IMO = not invincible. I think most would agree that if we had proof, if we knew, that Jones Jr's chin was good when he was younger, then he was the INVINCIBLE fighter at 168. But he never got caught flush or got involved in wars to the extent that we could know this. Jones Jr beat great opposition (Toney), but he was so dominant we never got to see how his chin held up, so because of his losses once he was shot, the doubt lingers with many fans. My own feeling is that Jones Jr had a perfectly decent chin. He got caught regularly by Montell Griffin in their first fight at light-heavyweight and he fought at heavyweight. Never flinched. The only reason he incurred KO losses (to two very good punchers IMO) in his mid-30s was that his bulking up in muscle up to heavyweight and subsequuent burn-off back to light-heavyweight ****ed with his body in ways RJJ himself didn't understand. His reflexes, co-ordination, punch resistance and resilience were shot to pieces. That's the only way to describe the change from the sensational fighting machine who embarrassed Glen Kelly, Clinton Woods, and John Ruiz in 2002-3, to the guy who got sparked by Tarver and Johnson in 2004-5. I think the closest suggestion to someone who could beat Jones at 168 was Sweet Pea's call of Ezzard Charles. However, I respectfully disagree. It's a valid viewpoint, as Charles should be in everyone's top 10 p4p of all-time, but at 168 I would strongly fancy Jones. If you look at Charles's record, he only had a handful of fights around 168, and although he had some excellent wins (Burley, Maxim), he also had some bizarre multiple knockdown losses (Jimmy Bivins, Lloyd Marshall). I think Charles was definitely better at weights higher than 168. In conclusion, I cannot state with certainty that Jones Jr was invincible at 168 because his chin was never proven to be strong and he would obviously be hit if he fought the best guys to ever fight at 168, but based on the evidence of the 1st Griffin fight, the fact he competed at heavyweight, and the way Hopkins and Toney struggled to lay a glove on him, my own opinion is that Roy Jones Jr at 168 was as close to invincible as it gets.
"I'm not one of these guys like Toney or Tyson who comes out and says they are unbeatable. Anyone can be beaten on a given night". Roy Jones Junior "Anyone can be beat." Iron Mike Tyson. There is no such thing. These boys knew it, I know it, and you know it.