In this note, a robust output feedback Fault-Tolerant Control (FTC) for a high-performance tracking problem of a Lipschitz nonlinear system under simultaneous sensor fault and disturbance is developed. The proposed scheme includes the design of an adaptive sliding mode observer which recovers the separation principle. A tangent-type barrier Lyapunov function is incorporated in the backstepping framework to maintain the system states in a prescribed performance bound. Moreover, the unknown estimation error is taken into account. Furthermore, the bounded initial condition assumption is relaxed by defining a time variable bound. The effectiveness of the proposed solution is numerically examined on a DC motor model.