 On May 1, 1916, Brennan achieved a second-round knockout of 6 foot, Buffalo native George "One Round" Davis, a competent heavyweight, in Rochester, New York.On May 4, 1916, he TKO'd Rodel in the third round at the same location.On May 16, 1916, Brennan achieved a sixth-round technical knockout of Al Williams at the Pioneer Sporting Club in New York City.