The last fight before the final round, Tommy crying to himself against the cage realizing he isn't going to win with a broken shoulder.
The entire scene of Paddy meeting Tommy in the casino. He attempts to commemorate his rescue of a marine in the war, only to find out that at the time, Tommy had been illegally fleeing his troop. Paddy tries to be understanding and supportive, but Tommy's having none of it and proceeds to give him a humiliating verbal beatdown and drives him away. Cut to the next morning when Tommy returns to the hotel to find his father a wreck once more, drunk again after one thousand days of sobriety, wandering around his hotel room as though lost and sobbing deliriously. This scene is painful enough through the sheer hurt and misery on Paddy's face, but even moreso for Tommy's response when faced with the scene: a quiet My God, What Have I Done? moment, followed by Tommy cradling his drunk father on the bed, petting his head and shushing him to sleep.