The self-determination theory (SDT) assumes that healthy motivation needs to be intrinsic in nature and that the basic psychological needs competence, autonomy and relatedness are prerequisites for intrinsically motivated behaviour. Intrinsically motivated students in turn show more persistence and understanding of classroom material. However, in secondary education, students often participate in performance-oriented classrooms with an extrinsic orientation and it cannot be assumed that the principles advocated by the SDT are automatically applicable in this context. We tested a model relating basic psychological needs via intrinsic motivation to persistence and performance at two waves using data from 476 students (aged 11-17 years) attending pre-vocational secondary education. Structural equation analysis showed that a partial mediation model with perceived competence also directly associated with persistence and performance fitted the data best at both waves. Interestingly, the strength of the effects varied across waves, such that relatedness and autonomy became negative predictors of intrinsic motivation for a familiar task. The practical and theoretical implications of these findings are discussed. (Contains 3 figures and 4 tables.)