ATLANTIC CITY, N.J. (AP) _ Ray Mercer, 225, Short Hills, N.J., stopped Tommy Morrison, 221 , Kansas City, at 28 seconds into the fifth round to retain the WBO heavyweight title; Michael Carbajal, 109, Phoenix, outpointed Jesus Chong, 108 1/2 , Tucson, Ariz., 10, light flyweights.