Delivering an effective online mathematics course at the university level is more challenging than the offline mode because of the method course content's nature. One of the strategies to answer the challenges faced in an online learning environment is the utilization of Open Educational Resources (OER). This descriptive case study research investigates students' satisfaction and performance in the Open Educational Resources (OER)--integrated online calculus course. This study involved eight students who took a calculus course entirely online. The lecturer used various OER, both integrated into Canvas and during the online meetings. Students were satisfied with the online calculus course since it has met their expectations. The online course content and use of OER, classroom environment, and lecturer facilitation were three components that students find valuable. Likewise, students' performance in the online calculus course is excellent, where all students got grades A. Although students' performances in Unit Test 1 and Unit Test 2 are not as excellent as other assessments, they demonstrate active participation during the online meetings, frequently use OER, and consistently fulfill all assignments. They succeed in developing digital learning activities as their pair works and learning videos about the application of integral as their group projects.