As Santiago grapples with his cramped hand, he hyperbolically describes how long he could stay with the marlin:
It is not the hand’s fault and you have been many hours with the fish. But you can stay with him forever.
Of course, Santiago can not stay with the marlin forever. The claim that he can, however, highlights Santiago's pride. Santiago alternates between recognizing his limits as a fisherman—limits th have grown as he ages and are exacerbated by fishing alone—and between making assertions like the hyperbolic one above. Santiago's pride fuels his victory: the belief that he was strong enough to fight the marlin helped him stay with the fish as long as was necessary. In this way, Santiago's battle with the marlin is akin to the arm wrestling match he describes starting on page 42, which concludes with Santiago deciding "he could beat anyone if he wanted to badly enough."
Although the claim that Santiago could stay with the marlin forever is hyperbole, Santiago was willing to die fighting the marlin, and he ended up catching the fish. Santiago may be prideful, but his pride is not misplaced, and he proves himself a talented fisherman over the course of the novella.