Achievement goals are motivational antecedents which play an important role in students' self-regulated learning (SRL). Achievement goals are also found to have an influence on students' learning outcomes. However, how achievement goals and SRL jointly affect learning performance is still an underexplored area of research, especially in computer-supported learning environments. This research added new evidence on the relationship between achievement goals, SRL behaviors and students' performance outcomes in a task of students diagnosing virtual patients in BioWorld, a technology-rich environment to help medical students practice their clinical reasoning skills. Multidimensional data (e.g. trace data, self-reports) were collected from 50 participants. Findings from this research demonstrated that performance avoidance goals positively predicted the SRL behavior of "link evidence." Performance and mastery approach goals had a marginal negative effect on the SRL behavior of "link evidence." Among the SRL behaviors traced, "order lab test" and "check evidence" positively predicted students' efficacy, while "link evidence" negatively predicted their efficacy. The SRL behavior of "check evidence" positively predicted students' confidence in making a correct diagnosis. Furthermore, performance approach goals negatively predicted the diagnostic confidence of learners. The instructional implications and the broader impacts for future research are discussed.