In balboa what were the many references and images to dogs through the story?

In fighting community, there is a famous saying "It's not the size of the dog in the fight, it's the size of the fight in the dog" , which originated from mark twain.
This quote means that when facing a stronger opponent, the most contributing factor is not the strength itself, but each fighter's ability and desire to fight.
This quote reflects Balboa's situation because he is clearly facing the opponent that much stronger than him.

Ibelieve that is true! but go with your gut.good luck!