This mixed-method study investigates the citation behaviour of a successful L2 postgraduate management student, Sofie, in two pieces of writing, written in response to two assignment tasks in two management modules. The tasks belonged to the same assignment type, but differed in the level of direction provided: one was a directed task, accompanied by lecturer guidance on readings, while the other was an open task, allowing students to select their own topic. The discourse-based interview approach (Odell, Goswami, & Harrington, 1983) was used to elicit Sofie's perceived citation functions, followed by quantifying the qualitative codings to allow for comparison. The findings show that some of the citation functions Sofie described were the same in both assignments, while others were task specific. Sofie used citations in both assignments to define terms and support her arguments. However, it was only in her assignment for the open task that she used citations to show the relevance of her chosen topic. Conversely, she frequently used citations to apply citees' concepts to her own analysis in the directed task, but not in the open task. We conclude by discussing the implications of our findings for L2 writing instruction. (Contains 5 tables.)