1905-12-20 (175lbs) Philadelphia Jack O’Brien w rtd 13 (20) Bob Fitzsimmons, Mechanics’ Pavilion, San Francisco, California, USA
1905-12-20 (175lbs) Philadelphia Jack O'Brien w rtd 13 (20) Bob Fitzsimmons, Mechanics’ Pavilion, San Francisco, California, USA. Referee: Ed Graney. Although seen by some as one of a series of eliminators to decide the heavyweight title, the Boston Daily Globe and others reported it to involve both the world light heavyweight and heavyweight championships. O'Brien was already claiming the heavyweight title, while Fitzsimmons' light heavyweight crown was on the line at the same time.
Once the fight got underway it was clear that O’Brien (164) was the faster, using good footwork to get away from trouble, while Fitzsimmons (165) looked for the punch to finish it. Throughout, O’Brien showed his ability to hit and shift, hurting Fitzsimmons badly in the fourth and flooring his rival in the eighth with a stiff right to the jaw. Although Fitzsimmons continued to come forward he was taking more and more punishment, and at the end of the 13th he collapsed in his corner with blood pouring from his nose and mouth, whereupon the referee awarded the fight to O’Brien. Fortunately, Fitzsimmons quickly recovered and left the ring unassisted.
Following O'Brien's victory, he was regarded by ‘certain sporting men’ as winning the heavyweight title based on the theory that the championship had reverted to Fitzsimmons on James J. Jeffries’ retirement.