Universities have strengthened their capacity to conduct teaching online since the COVID-19 pandemic, yet online teaching poses new challenges for teacher-student relationships (TSR). International research emphasizes the significance of TSR for learning, but there is a lack of research on how TSR is built in digital classrooms. This paper discusses teachers’ relational competence as manifested in online teaching. Microscopic Relational Analysis (MRA) was used to explore a university teacher’s relational competence, focusing on nonverbal communication. The analysis shows how changeable and vulnerable the TSR can be. This is a characteristic of TSR in teaching face-to-face, but it is hardly expected of TSR in online teaching. In addition, the study indicates that teachers’ nonverbal communication is an important feature in this context. The MRA suggests that a teacher’s sensitivity to detecting a student’s subtle cues is crucial for successful online TSR. Further, it is suggested that teachers’ relational competence is manifested along five patterns, where respectful communication during the student’s turn is essential. Overall, the study suggests the importance of teachers’ relational competence in fostering a positive and supportive digital learning environment and highlights the need for teacher training and professional development programs to enhance teachers’ relational competence in online teaching.