The skill you practice under easy conditions still needs a turn in real ones.

A skill rehearsed only in calm conditions is really two skills, and you have practised one of them. The version that survives noise, tiredness, an audience or a clock behaves differently, and the gap tends to appear at the exact moment it matters. Comfortable practice is where the movement gets built. Harder conditions are where you find out what falls apart.

Add one uncomfortable rehearsal before the real thing: with somebody watching, at speed, or late in the day when you are tired. Expect it to go worse than usual, and treat whatever failed as your list for next week.