Jaime Munguia enjoyed a winning debut in the middleweight division after stopping Gary O'Sullivan in the 11th round in San Antonio.

Stepping up from light middleweight, Munguia's first fight at a new weight ended in victory after battering Irishman O'Sullivan on Saturday.

Munguia (35-0) grew in confidence as the bout wore on and the Mexican sent O'Sullivan (30-4) to the canvas in the 11th round.

O'Sullivan's corner threw in the towel, forcing the referee to stop the fight at 2:17 at The Alamodome.