Santiago reveres Yankee slugger Joe Dimaggio. Dimaggio plays for Santiago's favorite team and is one of the best baseball players in the league.
As they share their meals, Santiago and the boy discuss baseball and the important players of the period, especially “the great DiMaggio.”
More importantly, thematically speaking, Dimaggio has played through pain.
Early in the book, Santiago identifies this fact. Dimaggio has bone spurs in his feet. Santiago does not know exactly what this condition implies, but knows that Dimaggio has had to continue to play through pain.
Santiago reflects on this on his fourth day at sea, after fighting through pain to keep the great fish on the line.
Santiago knows DiMaggio would be proud of him; he has no bone spurs but his back and hands are not good.
Santiago, el campeon, displays a tenacity and greatness of his own to match that of Dimaggio. Though Santiago's virtues are unsung, they are real nonetheless. The dignity that Santiago sees in Dimaggio is a dignity that he displays also.