This paper reports on the novel use of classroom videos by 71 pre-service teachers enrolled in a one-year graduate diploma pre-service teacher education program across three Australian universities. The classroom videos were of an experienced teacher delivering a Year-6 mathematics lesson. Students observed, discussed and debated practices that were evident. Data were collected via observation protocols and through recorded focussed discussions. Pre-service teachers, even at the early phase of their course, were able to articulate theoretical explanations for events occurring in the lesson. All students, irrespective of the progression in the course, lamented the absence of prior opportunities to engage in analysis and discussion of classroom lessons. The study reinforces the value of dialectical interactions focussed on authentic teaching scenarios.