In this paper, a new nonlinear control method is developed for a class of single input single output (SISO) non-affine nonlinear discrete-time system. The key strategy is to decompose the un-modeled dynamics into the sum of a known function depending on the data from the previous one time step and an unknown increment. The former is used to compensate for the un-modeled dynamics approximately. A new nonlinear controller is proposed to achieve stability meanwhile improving the performance of the closed-loop systems, which is different from those switching-based methods in the literature. Finally, through simulation based comparative studies, the effectiveness of the proposed method are justified.