The output tracking problem for a class of sampled-data nonlinear systems exposed in Nonlinear Block Controllable (NBC) form is faced. This paper considers both matched and unmatched perturbations. To formulate a desired sliding manifold on which the impact of unmatched perturbation is attenuated, the Block Control technique combined with the perturbation estimation, is implemented. A discrete-time sliding mode non-switching controller is synthesized such that the system state is driven toward a vicinity of the designed sliding manifold and stays there for all sampled time instants, avoiding chattering and reducing the matched perturbation effect. The effectiveness of the proposed technique is confirmed by simulation.