Discourse competence is an essential component of communicative competence and central to the mastery of academic writing. This article reports a three-tiered diagnostic assessment of two English as a foreign language (EFL) student writers' discourse competence in terms of textual features, composing strategies, and knowledge about academic writing. Drawing on extensive analyses of their writing samples, writer logs, and semi-structured interviews, we identified their discourse-level weaknesses and examined their writing strategies and academic writing knowledge status to ascertain their relationships with the observed weaknesses. Global coherence, which conveys the macros-level structure of the whole discourse, was found to be a shared problem of the two students. An investigation into their writing processes found that both students were deadline fighters whose poor time management seemed to account for the problems in their texts. Both spent too much time researching content knowledge but did not reserve sufficient time for writing and revision. Having limited knowledge of the disciplinary content and the required genre type and lacking adequate writing strategies were three salient blocks that impeded their composition of disciplinary essays. Based on the above, we propose a three-stage instructional procedure to facilitate novice EFL learners' development of discourse competence in English academic writing.