A veteran of 15 world championship fights, Antonio is a former three-time welterweight world champion - he won the WBO title in in March, 2002, and made seven successful title defenses. He won the IBF title in April, 2008, then vacated the title and won the WBA title in July, 2008.
He is coming off a 12 round decision loss against former flyweight, junior featherweight, super featherweight, lightweight, and welterweight world champion Manny Pacquiao in his last fight on November 13.
Antonio's right orbital bone was fractured in the fourth round of the fight.
In an interview with Felipe Leon of Fightnews.com, Antonio said, "The fight changed after the fourth round. He caught me with an uppercut and hurt my eye and after that, I couldn't see. I was told that I hurt him in that round but I didn't see it, or else I would have finished him right there.
"Like every Mexican, the corner would ask me if I wanted the fight stopped and I said, ‘No, I am good.' I never thought in stopping the fight. My corner did mention it to me but I felt fine physically with my conditioning. Yes, I couldn't see because of my eye, but I would tell them that I wanted to keep going. The referee checked me out and made sure I could continue. I felt fine. I couldn't see but I wanted to finish the fight. [End Leon item]
Antonio is experienced against top opposition. He has fought world champions Manny Pacquiao (L12), Shane Mosley (TKOby9), Miguel Cotto (TKO11), Kermit Cintron two times (KO6, TKO5), Paul Williams (L12), Joshua Clottey (W12), Daniel Santos two times (TL10, NC1), Andrew "Six Heads" Lewis (KO2), Frankie Randall (TKO4), and Sergio Martinez (TKO7).
Antonio was the underdog in many fights early in his career, and had a few setbacks in his first two years as a pro - he was 9-3 in his first 12 fights.