After a loss, “how could I have done it better?” beats “that was so unlucky” every single time.

Luck is real and it is also useless to you afterwards. A loss you file under bad luck teaches nothing and leaves you exactly as prepared as you were before it. The other question finds the two or three things that were inside your control, which is a shorter list than it feels like and the only one you can work with.

After the next result that stings, give yourself one day and then write three lines on what you would do differently. Keep them specific enough to practice. If you genuinely find nothing, that is fine, and it is a much better answer once you have looked.