This paper studies a class of coupled dynamical systems consisting of an actuated dynamical system interconnected with an unactuated dynamical system. The actuated dynamical system is considered to have a measurable state for feedback control, whereas only the output is available from the unactuated dynamical system. Specifically, the control objective for this class of dynamical systems is to allow a desired subset of the state of the actuated dynamical system to follow given commands in the presence of uncertain parameters and unactuated dynamical system coupling. To this end, our contribution is a mixed state and output feedback framework in the context of model reference adaptive control, which is predicated on integrated nominal and adaptive control laws. The key feature of the proposed model reference adaptive control architecture is to guarantee stability of the closed-loop coupled dynamical system as well as to assign user-defined bounds on system error trajectories utilised by the adaptive control law for achieving a prescribed level of overall system performance.