Inquiry on success of online language teaching has commonly focused on basic or intermediate language courses. This inquiry explores the success of an advanced‐level online Spanish grammar course. Two sections of the course are compared: one is proposed face‐to‐face, and the other is proposed fully online. The aims are both to measure students' achievement in the two sections, and to better grasp specific defiances faced by online teaching. The inquiry displays that there was significant improvement (learning) in the online section, and that learning is indeed comparable to that displayed in the face‐to‐face section. However, the study distinguishes, identifies and debates one specific defiance faced by an online format: the different nature of the interaction between the learner and the learning environment.