If you ever find yourself defending a position, explaining why, or justifying anything, it means you have been defeated. It means you have not been able to accept the others point of view, or the fact that you may be wrong. Fear has conquered your mind and your heart. Your defences are up and you are running scared. It's not that the other person has conquered you, it's the self-created fear that is in control.
Until you can accept the other (you don't have to agree) and you are not threatened by the other, your victories will be delayed. It's a funny old world when true winning is accepting not resisting, when victory is found in the wisdom to stop fighting and to begin engaging.