Control
Given an equality of strength and skill, the victory in golf will be to him who is captain of his soul. (Arnold Haultain, late British writer)
In solo sports, where you may be competing against other individuals, the real test is how well you are in control of your own game. Whatever the sport, there are multiple challenges to your skill, knowledge, endurance, and even your conduct. Self-control, of course, is a challenge in the daily lives of all of us. Without it, we will surely fail at some point.
Better to be patient than powerful; better to have self-control than to conquer a city. (Proverbs 16:32)
So prepare your minds for action and exercise self-control. (1 Peter 1:13)