Good sportsmanship we hail, we sing,
It’s always pleasant when you spot it,
There’s only one unhappy thing:
You have to lose to prove you’ve got it.

Richard Armour (1906–1989) American poet and author

Poem (1956-01), “Good Sportsmanship,” American Legion Magazine, Vol. 60, No. 1
    (Source)

Collected in his Nights with Armour (1958).