Passing The Last Test Doesn't Mean You Don't Study For The Next
Just because you passed the last test you aren't guaranteed to have the same success on the next one. Yet you always have winners that get cocky. The hare stops to take a nap because it expects to win, and we know how that turned out.
I see this in dance with my girls, they often compete with others groups from our own studio or see the same studio and dancers at another competition. How they placed last time doesn't mean anything. You have different judges and different levels of performance.
Finding success in the past should encourage you though. You know that you are capable of doing it, just need to recognize it isn't guaranteed. You still need to put in the work and effort that got you there last time. You might need to do even more because this time the competition recognizes you are the defending champ.
Nothing in your past guarantees anything for the future. Past success doesn't guarantee future success anymore than past failures have no indication on if you will be able to succeed in the future or not.
Take the lessons from the past you need to, but then leave it in the past, keep your focus on the future.