Defense or not, but a coach or anyone will definitely tell the success they got before when they played not according to what was desired. That will be a weapon that they always carry, both in front of the media and in front of supporters.
However, supporters or management will not see their achievements in the past, because what they will see is how they perform now. If we only talk about past success, then we will not see coaches who are fired for failing in one season.
However, it is legitimate for coaches to do it to defend themselves, but it must also be accompanied by better results in the next match.