When we talk about a person being off his or her game, we are talking about the inner game. I remember a Monday Night Football fiasco in St. Louis back in 1983. Even the coaches suffered major lapses of concentration. It is not trying to concentrate. It is not thinking hard about something.
Concentration is fascination of the mind.
Where there is love present, the mind is drawn irresistibly toward the object of love. It is effortless and relaxed, not tense and purposeful. When watching . . . If your eyes are squinting or straining, you are trying too hard. Let the ball attract your mind, and both it and your muscles will stay relaxed.