The Man Who Thinks He Can Walter D. Wintle:

If you think you are beaten, you are
If you think you dare not, you don’t,
If you like to win, but you think you can’t
It is almost certain you won’t.
If you think you’ll lose, you’re lost
For out of the world we find,
Success begins with a fellow’s will
It’s all in the state of mind.

If you think you are outclassed, you are
You’ve got to think high to rise,
You’ve got to be sure of yourself before
You can ever win a prize.
Life’s battles don’t always go
To the stronger or faster man,
But soon or late the man who wins
Is the man who thinks he can.