By Manuel Perez: WBO super flyweight champion Fernando Montiel (36-2-1, 27 KOs) overwhelmed former WBA super flyweight champion Martin Castillo (33-3, 17 KOs), stopping him in the fourth round on Saturday night at the MGM Grand, in Las Vegas, Nevada. Castillo, 31, looked listless and out of it as early as the first round, as was quickly knocked down by a left hook by Montiel. Castillo was staggered at the end of the 3rd round after getting hit with a big left hook from Montiel. Castillo was hurt again in the fourth round by a right hand, and then retreated to the ropes where Montiel hit with with combination and then left hook the body, dropping Castillo for the 10 count. Referee Joe Cortez stopped the fight at 1:56 of the 4th round.