As has already been said, he didn't start boxing at all untill his 20's which makes his achievements quite amazing! He was avoided for many years and he spent alot of time over here (UK) knocking out some decent fighters, regularly fighting on undercards to try and earn some cash. He's always been a very, very talented athlete and fighter. The Cintron fight was his big coming out party when hardcore fans really started to take note of him. I remember when he signed to fight Williams on very, very short notice after Pavlik pulled out, and i said that it was a huge mistake from Williams to take it because not many know just how good Sergio is. He was awesome that night and just about won it on my card (a single point from memory), but obviously the rematch spoke volumes. Won alot of money on the Pavlik fight when Martinez was a big underdog! He's been this good for a number of years now, he just hasn't been given a chance due to some **** promoting, bad managing and boxing politics.
first time i saw him live was against russell jordan. pretty impressive performace. the one that got him his break was against bunema. when bunema had that great little run with karmazin and matthysse. sergio looked like a semi remarkable fighter that bunema might catch and finish. [ame]http://www.youtube.com/watch?v=TgwbYUo4LNs[/ame] but i do sort of remember seeing this on google videos. when there was talk of williams making a comeback.
Late starter, poor management, injuries with his left hand, losing to Margo, moved to spain and got managed terribly then he dominated and KO'd richard williams, got some american fights under his belt, got robbed against Cintron and then hit the mainstage.