Stress isn’t a bad thing. It makes you focus. Focus is a good thing.
The trouble comes with distress.
Distress can cause you to panic. Panic will cause you to fail.
The easiest way to avoid distress is to keep your eye on the big picture. Don’t let the small stuff get under your skin.
Your flight delayed? Don’t panic. Getting upset won’t get you there faster, it will just cause distress (and may get you kicked off the flight).
Take a moment to reflect on your life. Realise how big the world is, and how small your problems are in the grand scheme of things.
Work as hard as you possibly can. Leave nothing on the field. Know in your heart that you gave it your best.
Do that and you won’t feel distressed. What will be will be.