The purpose of this study is to explain students' perceived relevance of playing an educational game as a means for development of discipline competence. Based on self-determination theory and the concept of personal interest, we propose that: Satisfying students' basic needs for competence, autonomy, and relatedness when playing educational games is critical for arousal of intrinsic motivation in learning-through-gaming; Students' interest in the core subject and their intrinsic motivation in learning-through-gaming are important for their perceptions of how relevant they believe the gaming session is for the discipline they are studying. The results from an empirical study indicate that arousal of intrinsic motivation in the ongoing gaming session is more important than pre-gaming interest in the core subject for participants' post-gaming perception of how relevant such gaming is as a means for developing their discipline competence. The results also indicate that satisfying basic needs for competence, autonomy, and relatedness is critical for arousal of intrinsic gaming motivation. Our findings have implications for the choice of pedagogical means when utilizing educational games as a complementary alternative to traditional learning methods. To that end, we offer directions for future research. (Contains 4 tables, 1 footnote and 2 figures.)