Replay the loss once for lessons, then replay a win once for belief. Both are training.

Reviewing only the failures produces an accurate list of weaknesses and a badly distorted picture of yourself. Both halves are data. Going back over something that went well is not vanity; it reminds you what your actual capability looks like, which you need when deciding whether to continue. Skill and nerve are separate things and they get trained separately.

After the next loss, do one honest review and then deliberately revisit something you did well. Keep a short record of good performances for exactly this purpose. Read it before the next hard thing.