Adaptive controllers with closed loop reference models have guaranteed transient performance due to the additional design freedom available in them. However, robustness in the presence of both matched perturbations and time delay is not guaranteed, which is a necessary requirement for most of the safety-critical systems, such as, aerospace applications. This study attempts to achieve guaranteed transient and steady state performance with improved robustness in the presence of both matched perturbations and input delay by incorporating a proportional–integral (PI) compensator in the feedback loop of the closed loop reference model reference adaptive control (MRAC) architecture. The proposed system also reduces high frequency oscillations in control channel without disturbing the relative order of plant. The parameters of PI compensator have been tuned using genetic algorithm. Effectiveness of the proposed work has been validated on standard numerical examples using simulation results and the performance has been compared with similar and recent works.