Forum:The term "Control" sort of confuses me

For example, the card Machina Fortress, mentions that when it is destroyed by battle, I can target 1 card my opponent controls and destroy it. Does this mean I can target any card that the opponent has on his/her side of the field, regardless if they are Set or face-up and active on the field? Does this apply to every other card with a similar effect involving "Target 1 card on the field"?--NickTheForbiddenOne (talk • contribs) 15:13, October 21, 2012 (UTC)