The nonlinear supermatrix σ-model is widely used to understand the physics of Anderson localization and the level statistics in noninteracting disordered electron systems. Here we develop a supersymmetry approach to the disorder averaging in the interacting models. In particular, we apply supersymmetry to study the Sachdev-Ye-Kitaev (SYK) model, where the disorder averaging has so far been performed only within the replica approach. We use a slightly modified, time-reversal invariant, version of the SYK model and perform calculations in real-time. As a demonstration of how the supersymmetry method works, we derive saddle point equations. In the semiclassical limit, we show that the results are in agreement with those found using the replica technique. We also develop the formally exact superbosonized representation of the SYK model. In the latter, the supersymmetric theory of original fermions and their superpartner bosons is reformulated as a model of unconstrained collective excitations. We argue that the superbosonized description of the model paves the way for the precise calculation of the window of universality in which random matrix theory is applicable to the chaotic SYK system, and for the derivation of the corresponding Wigner-Dyson eigenvalue statistics.