When Tony, Sil, and Bobby are in the restaurant, the strains of the Intermezzo from the Mascagni opera Cavellaria Rusticana are heard. Tony and Sil were mimicking the slow motion boxing scenes from Raging Bull, obviously a nod by them (and perhaps by Chase) to the Scorcese/De Niro film that prominently featured that theme.
That was not the movie that came to my mind, however. Cavellaria Rusitcana was the musical backdrop for the climax of Godfather III, with the Intermezzo scoring the scene where Mary Corleone is killed by stray gunfire meant for her father. It's an unbelievably gorgeous piece of music, very, very poignant. For my sensibilities far more apropos for its use in Godfather III than in Raging Bull.
As with so much in this show, I wonder if the "obvious" association was the most important one. Was it just a moment to show two Italian mobsters reacting with ethnic pride to an iconic Italian actor and film director portraying the life of a tough Italian boxer who could take anyone's punch and not go down? Or was it musical foreshadowing that Tony will suffer a tragedy of similar nature and dimension to the one Michael Corleone suffered at the end of GFIII?
Tony, his spirits crushed after b-lining to the fridge first thing in the morning: "Who ate the last piece of cake?"