
Saucedo, a Mexico-born American fighting in his adopted hometown of Oklahoma City, delighted his fans when he sent Hooker to the canvas with a heavy right hand in the second round.
But Hooker found his rhythm and took charge in an aggressive seventh.
He was credited with a knockdown when he sent Saucedo reeling into the ropes and when the fight resumed after a standing eight-count Hooker pummeled the challenger until the referee jumped in to call a halt at 1:36 of the round.
Saucedo suffered his first defeat in 29 fights.
Hooker improved to 25-0-3 with 17 knockouts as he made the first defence of the title he won on June 9 with a split decision victory over England’s Terry Flanagan in Manchester.