The COVID-19 pandemic forced several Bangladeshi private universities to move from in-person to online classes. This paradigm shift has facilitated a unique window of opportunities to harness the untapped potentials of e-learning practices in Bangladesh. However, it has posed a myriad of coping challenges for Bangladeshi students. This exploratory research was conducted to identify the seized learning opportunities along with the critical challenges experienced by the students while learning from online classes at a private university of Bangladesh. This research adopted a mixed methodology of combining both qualitative and quantitative approach for holistic insights. Quantitative data was collected through an online questionnaire survey on a representative and diverse sample size of 745 participants from ten different departments. Semi-structured in-depth interviews consisting of closed and open-ended questions were conducted on 20 respondents for in-depth findings. Primary findings demonstrate the underutilized potential of online classes such as adaptive personal learning, peer learning, gamification, collaborative problem solving, synchronized and asynchronized communications etc. The primary challenges include inadequate infrastructural arrangements, lack of uniform and coherent guidelines, non-existence of incentives, limited access to devices, interrupted internet connectivity, poor speed of internet, high data price, limited or no prior orientation to online learning tools and techniques, tedious online class schedule, increased summative and formative tests, fatigue from overusing virtual platforms and physiological issues such as eye-strain, backpain, headache, dizziness from prolonged online classes, absence of face-to-face socialization etc. Based on these findings, this study recommends a few pragmatic strategies to harness the untapped opportunities of online learning and further ensure the viability and sustainability of online education in Bangladesh. Keywords: E-learning; opportunities; online classes; Bangladesh; COVID-19.