 In a late-career match on May 11, 1923, Mosberg defeated New Jersey boxer Willie Shaw in Hoboken, New Jersey, in a twelve-round newspaper decision.Near the end of his career on August 14, 1923, Mosberg had a close ten-round fight with Jack Rappaport at the open air arena of Broad Athletic Club in Newark, New Jersey.Mosberg suffered from a six-inch disadvantage in height, greatly limiting his reach against Rappaport but won the bout in the decision of the "New York Evening Telegraph", who wrote "Sammy had a clear lead over his opponent all the way".