Flow

Flow, in the zone, a state that many athletes assume when in competition. It applies to martial arts and can apply to self-defense. It is an optimal state in which you feel totally engaged in an activity. You are neither bored or anxious; you don't question your own inadequacy; hours will pass with out notice. You seek an activity for its own sake, not for the rewards it brings. It is usually a solitary pursuit. 

It occurs in conditions in which people "become independent of the social environment to the degree that they no longer respond exclusively in terms of its rewards and punishments." It allows you to be persistent, tenacious and clear sighted. It also allows your mind to remove itself from the stress, strain and anxieties of the fight. 

It requires reality based stress adrenaline induced training and practice to gain the experience to overcome the effects and drop into a flow or zone that allows you to act appropriately. It means maintaing a balance of body, mind and spirit so that all the effects that affect the body, i.e. adrenaline dumps, the mind, i.e. the chemicals that hinder the mind from the adrenaline dump, fear and/or anger, etc., and the spirit or that mind-set that allows us to break the freeze and make effective use of things like using the OODA faster than your adversary.