Recent modifications and adaptations to the Teaching Games for Understanding model (Kirk and MacPhail, 2002) have proposed that in addition to the core elements of modified game form, tactical awareness and game performance supplemental interfaces also exist between the core elements of the model. These interfaces highlight the critical role of learners' socio-cultural expectation of the game form, cue perception capability and technique selection in determining students' tactical game performance. To date, there remains a dearth of research evidence which has served to validate these perspectives and provide a systematic evaluation of the revised TGfU model. The didactic framework (Amade-Escot, 2000a) is a naturalistic research methodology which foregrounds content as the determinant feature in understanding the teaching-learning process and may provide an effective method to investigate the dynamics of student learning during tactical teaching. The purpose of this study was to provide a didactic analysis of student tactical learning within an invasion games unit taught using the tactical approach. A critical didactic incident (CDI) methodology was employed with the “evolution of the didactic contract” (Amade-Escot, 2000) used to determine significant perturbations in the learning process. Results revealed that major breaches in the didactic contract of the knowledge intended to be taught and actually learned by students occurred at several stages of the TGfU approach. Significant breaches in the didactic contract and divergence from intended learning goals occurred during the transition from modified practice form (e.g 2v1) to more complex game form (e.g. 3v3). The post-game question and answer pedagogy was found to be relatively ineffective in facilitating repeated tactical behaviors in the more complex game form. Results also revealed that teacher-directed interventions that provided instant verbal feedback relating to the recognition of critical cues (e.g. identification of open player signal) facilitated improved tactical decision-making and performance behaviors during game play. Specific, progressive, aligned game constraints were found to increase frequency of desired tactical responses and reduce breaches in the didactic contract. These findings lends some support to recent theorizations on the situated nature of learning within the TGfU approach and the complex dynamic impact of the physical and social environment on student game performance. Specifically, the issue of design of game constraint and the provision of timely cue recognition feedback were found to be critical to the alignment of intended tactical responses during game play.Keyword(s): performance, research, youth sports