<p>This paper is concerned with the problem of prescribed performance tracking control for the strict-feedback systems with unknown virtual control coefficients. To deal with the problem, a novel fuzzy control approach based on an improved command filter is proposed in this paper. Herein, the fuzzy logic systems are employed to deal with the unknown nonlinearities and design the command filter. Then, a self-adjustable performance function is constructed to relax the initial condition in the sense that it can automatically adjust the performance boundaries based on the sign of the initial tracking error. This renders the controller implementation more flexible. Furthermore, it is capable of regulating the overshoot, settling time, accuracy, and peak value of the tracking error. The Lyapunov analysis shows that all the signals in the control systems are bounded, and the tracking error evolves within the predefined performance envelopes. The simulation results illustrate the theoretical findings.</p>