Objective This cross-sectional study examined associations between wheelchair sprint and anaerobic power (measured in the lab) and wheelchair mobility performance (measured in the field) among two groups of wheelchair tennis players. Additionally, construct validity was assessed for both lab and field tests. Design Nine amateur and nine elite wheelchair tennis players performed a Sprint and Wingate test on a wheelchair ergometer in the lab and a Sprint, Illinois, and Spider test in the field, with inertial measurement units on their wheelchairs. Associations were assessed using regression analyses, and construct validity was assessed with an independent t test (elite vs. amateur). Results The strongest associations were observed between lab outcomes and field sprint power (R2 > 90%), followed by peak linear velocity and test duration (R2 = 77%-85%), while peak rotational velocity showed the lowest associations with lab outcomes (R2 = 69%-80%). The elite group outperformed the amateur group on all test outcomes. Conclusions Despite differences in lab- and field-testing methodologies (e.g., trunk influence, linear/rotational components), the strong associations indicate overlap in measured constructs. Field testing offers valuable insight into practical performance, whereas lab testing enables in-depth biomechanical and physiological analyses. All tests effectively discriminate between elite and amateur wheelchair tennis players.