Game theory is the theoretical context of three compositions by Iannis Xenakis: Duel (1959), Strategy (1962) and Linaia-Agon (1972). The first two works oppose two orchestras, or more precisely two conductors, in a musical battle. The basic structure differs only in the size of the ensembles (Duel is written for two orchestras of twenty-eight musicians each, while Strategy is composed for two orchestras of forty-six musicians each), the tactics (i.e. the musical material) and the complexity of the gain matrices. Linaia-Agon, for horn, trombone and tuba, is a later composition, combining completely determined parts, and a part whose structure is determined by game theory. The general aspects of Duel, Strategy and Linaia-Agon having already been presented in other studies, we will mainly focus on the formal aspects of Duel and the structure resulting from the underlying use of the opposition model governed by the theory of the games. This text takes a computational and empirical musicology approach and identifies the dynamics derived from the model, with the performed musical structure. We carried out several computer simulations of Duel to study its behavior and the structures generated, according to the methods of “playing.” Duel is to be performed by two conductors who, per Xenakis’s instructions, will make choices in real time. These choices must follow precise instructions in relationship to the “game matrix,” provided by the composer. From our point of view, the choices of the opponents, in the context of a performance, will have a significant influence on the musical form generated. The main purpose of our research is to be able to guide conductors on the different “outcomes of the battle” according to their decisions.