The present work describes an experience of educational innovation in a university context. Its aim was to determine the relationship between students' frequency of use of online self-assessment with feedback and their final performance on the course, taking into account both learners' motivation and perceived usefulness of these resources for their learning process. Furthermore, we studied the relationship between metacognitive variables and academic performance and/or execution of activities aimed at learning the course content. To this end we created self-assessment material with the "Hot Potatoes" educational program and assessed the degree to which students took advantage of the tool, their satisfaction with it and their perceived knowledge, using ad hoc questionnaires. The results indicate better academic performance in those students that use interactive self-assessment. It should be pointed out that even students with low motivation levels made use of this teaching tool. Finally, a relationship was found between metacognitive variables and students' effort and performance. We discuss the need to include self-assessment in the curriculum, with a view to improving students' metacognitive knowledge.