 In his last reported bout, on October 8, 1923, Mosberg lost to local boxer Jack McFarland in a close eight-round points decision at Dreamland Park in Newark, New Jersey.McFarland had the stronger punch, and was able to dominate the infighting, a skill the more experienced, but battle-weary Mosberg had excelled in his earlier boxing career.McFarland was a respectable welterweight who would meet exceptional boxer Lew Tendler twice, and Benny Valgar once, but would not fare well against them.