"Play tennis without fear of defeat, and because it's fun and you enjoy it, or don't play it at all. There is no disgrace in defeat. The only disgrace is in quitting in or "dogging" a match. There is no disgrace, no blot on your escutcheon, in admitting that there are players who can beat you, either in a match, in a set, or on any given shot. You don't have to try and prove it was an accident. In the first place, nobody believes you, so you simply appear ridiculous, and in the second place, nobody cares but you, and you know the truth. All these alibis and explanations take your mind off the really important thing, which is, or should be, your match. If done to excess, this sort of thing will destroy your concentration, and bring about the very thing you fear, defeat."
Bill Tilden, America's First Great Tennis Superstar,
How to Play Better Tennis (1950) in Chapter: Courage
Video: Bill Tilden