Fear - "concern over an outcome that has yet to happen". Based on this definition fear can't exist in the present. Thus the old adage to "stay in the moment".
Wish I could do that more than I do. I understand it, but my mind still has a tendency to wander more than it should. When I'm playing/scoring my best I really do stay in the moment, commited to my shot, my procedure, my decision, etc. When I'm off I can almost always look back and see indecision, concern about results, and so on. And it's always tougher in bigger tournaments for me.
I still love the game even if I do have some have some worries and fears.