We propose a model for how therapeutic strategy, alliance, and epistemic trust interact to foster or hinder therapeutic processes. Four individual mentalization-based treatment (MBT) sessions were subjected to an in-depth qualitative comparison and interpretative phenomenological analysis. Two sessions had high adherence and quality ratings, and two exemplified low evaluations. The sessions were from an MBT program for patients with borderline personality disorder. The high-rated therapists were more prone to strategically identify and investigate maladaptive patterns, were more challenging, and brought the patients out of their comfort zone. This therapeutic endeavour seemed to facilitate therapeutic alliance and a productive therapeutic process. Low-rated therapists seemed to be brought out of their own comfort zone (e.g. transferences/counter-transferences), and attempted to amend the relational atmosphere by being supportive. In these sessions, the therapeutic alliance seemed weak, and therapeutic progress was not observed. When therapists strategically and competently challenged problematic patterns, despite disclosing discomfort, alliance was strengthened. It seemed that a clear therapeutic strategy, and skilfull battling of the patients’ comfort zone, fostered the therapeutic process. We hypothesize that epistemic trust may develop as a product of a fruitful and persistent focus on tasks and goals in therapy.