Dynamical approach to decisions and actions in team sports suggest that decision making can emerge from attacker-defender dynamics sustain on perception- action couplings. The general aim of this research is searching a lawful description of decisional behavior in 1vs1 in rugby. In our research distinct task constraints of rugby, may display similar instances of interpersonal coordination. Our methods used a 3D image measurement technique and artificial neural networks. From data we identify chaotic features, which originated the conceptual model that describe dyadic behavior with three coordination patterns hypothesized as attractors. The first step to model measurement was identifying a collective variable. The data indicated: i) decision-making in rugby characterized as a self-organized process; ii) two nested control parameters; iii) critical periods as 'open windows' to regions of criticality. Attacker-defender system as a whole can be described by order parameter dynamics. We formally model a three attractor's task to described dyads behavioural dynamics using differential equations and potential functions.