i tested mentality a lot before, they affect your stamina a lot and can change your result. my teams were goonskies (4) and rags to riches (1) set on all of the settings
goonskies on hard attacking vs rags on hard defending will average out around 6-1
and vice versa 8-0
the reason why hard defending is better is because the opponents players are too reckless? sounds about right. on consecutive games i set them on hard defending to conserve stamina

not sure if one can find out the opponents mentality other than to ask the person