Jessie Magdaleno outclassed Yenifel Vicente before the Dominican was disqualified after multiple low blows.
Magdaleno (28-1) knocked down Vicente (36-5-2) twice during what was a largely dominant performance in their super-featherweight bout in Las Vegas on Thursday.
The American former WBO super-bantamweight champion was in control before Vicente landed multiple low blows in the fourth round.
Vicente was disqualified after further low blows in the final round, having received numerous point deductions during the bout.
Magdaleno made a fast start and he knocked Vicente down with a left hand in the corner in the first round.
The fight threatened to turn ugly in the fourth round as Magdaleno continued to largely control proceedings.
Vicente was deducted multiple points for low blows, following one up with a head shot as the referee came to separate the boxers.
Magdaleno's response was another knockdown in the fifth round, this time with a right hand.
With Magdaleno on track for victory, Vicente landed yet another low blow to begin the 10th round and was deducted a point once more.
It would, eventually, lead to a disqualification as Vicente produced another low blow, leading to the fight being stopped.