Tracking of a reference signal (assumed bounded with essentially bounded derivative) is considered in the context of a class Sigma(rho) of multi-input, multi- output dynamical systems, modelled by functional differential equations, affine in the control and satisfying the following structural assumptions: (i) arbitrary-but known-relative degree. rho >= 1; (ii) the "high-frequency gain" is sign definite-but possibly of unknown sign. The class encompasses a wide variety of nonlinear and infinite-dimensional systems and contains (as a prototype subclass) all finite-dimensional, linear, m-input, m-output, minimum-phase systems of known strict relative degree. The first control objective is tracking, by the output gamma, with prescribed accuracy: given lambda > 0 (arbitrarily small), determine a feedback strategy which ensures that, for every reference signal r and every system of class Sigma(rho), the tracking error e = y - r is ultimately bounded by lambda (that is, parallel to e(t)parallel to < lambda for all t sufficiently large). The second objective is guaranteed output transient performance: the tracking error is required to evolve within a prescribed performance funnel F phi (determined by a function phi). Both objectives are achieved using a filter in conjunction with a feedback function of the tracking error, the filter states, and the funnel parameter phi.