In case you usually starts your highest quality players (those 5 or 6 star as you mentioned) and these players recently poorly perform, you should try to leave them to the bench for a period. For short term success, I believe we should use the best performing players instead of highest quality players.
Quality must be a factor affecting match results. But match results are not simple math of comparing qualities of players. There are many other factors (player form, formation, etc)