Not necessarily - most of my games (especially in the Cup) are played with defensive/counter mentality as I'm usually playing against higher Level/better Q teams. I win more than I lose, and score more than one goal in the game about 80% of the time... One of the Palace Casuals League Championships listed below was achieved by playing almost the whole season using 4-5-1V formation, with defensive/counter tactics.
Another tactic I've used in away Legs where I've won at home without conceding in the 1st Leg in the Cup is to go attacking until I get the away goal then change to defensive. Usually the away goal in this instance means that the opponent has to score one more than you have to win the tie, and it eliminates the possibility of extra-time and penalties...