New Delhi, June 6 -- As a word, "endurance" has a rugged heft to it. It speaks of fortitude and spirit and summons images of mountaineers in thin air and marathoners at the teetering edge of exhaustion. It is the name of Ernest Shackleton's ship as he sailed for the Antarctic and should have been the title of Rafael Nadal's new documentary. This too concerns a voyage to the far reaches of suffering.

Suffering is the heart and veins and ligaments and bones of Rafa, the four-part documentary just released on Netflix. Suffering is Nadal's religion, badge, choice, addiction and challenge. Sometimes even he is not certain if it is worth it.

We're familiar with Nadal's willingness to scrap and to offer all of himself to a cause-every point be...