Juan Diaz had little trouble defending his WBA lightweight title Friday, stopping Billy Irwin at 1:27 in the ninth round of a lopsided fight.
Diaz, 21, the youngest reigning world champion, got off to a fast start and controlled the action throughout with his devastating left hook.
Diaz (27-0, 12 KOs) dropped Irwin in the second round, staggered him plenty more times and then finished him off with a flurry of punches against the ropes that forced referee Earl Morton to stop the bout.
By that time, Irwin (42-6) was squinting through a badly swollen right eye and was rarely fending off Diaz.
Diaz, Houston's first world boxing champ since George Foreman regained the heavyweight crown in 1994, was an overwhelming success in his first hometown title defense.