This paper presents a real-time implementation of an adaptive super-twisting (ASTW) controller. This work deals with the stabilization challenging problems of underactuated mechanical system subject to parametric variations and state- and time-dependent disturbances. Due to the low number of control inputs compared to the number of DOFs, the proposed approach has been designed based on an explicit global change of coordinates. The stability analysis of the resulting closed-loop system was performed based on Lyapunov’s theory. Extensive experimental investigations were conducted on the inertia wheel inverted pendulum (IWIP) to demonstrate the robustness of the proposed solution. These experiments include a real-time comparison with existing control solutions from the literature, providing a detailed analysis of performance, effectiveness, and robustness under various conditions. Quantitative evaluations were carried out based on different performance criteria, highlighting the practical applicability and superiority of the proposed control strategy in real-time scenarios. The results from both numerical simulations and physical experiments demonstrate the controller’s capability to maintain stability and performance despite the presence of disturbances and parametric variations.