The online game industry is a rapidly growing Internet-based business that has become very competitive in recent years. Game vendors have the option of designing online games in such a manner that they can match players against other players. Therefore, the interesting question is to identify conditions in these human-computer-human interactions that can motivate players to be engrossed and play more games and for longer periods of time. We approach this issue using a novel combination of mathematically based Tournament Theory and behaviorally oriented Flow theory to propose that when players' skills are equally matched, the challenge intensity of the game is moderate and players will play more games and for long. We also propose that individual traits such as performance goal orientation will moderate these effects. We test our ideas with a laboratory research design. Our preliminary findings provide support for our ideas.