For when the One Great Scorer comes to mark against your name,
He writes — not that you won or lost — but how you played the Game.

Grantland Rice (1880-1954) American sportswriter

“Alumnus Football,” l. 63ff (1908)
    (Source)

Often paraphrased, "It doesn't matter whether you win or lose, but how you play the game."

For more information on variations in this poem, and quotations from it, see here.