For mechanical systems described by Euler-Lagrange equations and involving high-order interconnections, this paper proposes a decentralized control, which guarantees the uniform ultimate stability when the control objective is tracking a smooth desired trajectory. The controller design is based on some physical properties of such systems and Lyapunov design methodology [3]. The application of the proposed controller to robot manipulators is presented, and experiment results are included to illustrate the performance of the proposed control algorithm.