First off, defensive marking systems in soccer cannot be applied under every condition. If the defense is under severe threat or is outnumbered, there is no point in talking of zonal or man to man defense. When a team is defending a set piece or is in close proximity to its own goal, the rules of defensive systems no longer apply. In those cases, one must emphasize on good individual positioning and intelligent decision-making. For example, if a defense is outnumbered 3 to 2, the fullbacks need to be thinking of how to delay the opposition. (Delay, Denial, Destroy, Develop)