We study dual strong coupling description of integrability-preserving deformation of the O(N ) sigma model. Dual theory is described by a coupled theory of Dirac fermions with four-fermion interaction and bosonic fields with exponential interactions. We claim that both theories share the same integrable structure and coincide as quantum field theories. We construct a solution of Ricci flow equation which behaves in the UV as a free theory perturbed by graviton operators and show that it coincides with the metric of the η−deformed O(N ) sigma-model after T −duality transformation.(1.5)Clearly, this procedure breaks the left symmetry, but preserves the right one. It can be shown that the model is still enjoys the zero curvature representation and hence possesses the integrability property. In this paper we consider the case of O(N ) sigma-model, i.e. we take G = SO(N ) and H = SO(N − 1). Integrability of this sigma-model at the quantum level has been first demonstrated by Polyakov [10]. As QFT O(N ) sigma-model corresponds to an asymptotically free theory with a dynamically generated mass scale. It describes scattering of N mesons in the vector representation of the global O(N ) group [11,12]. The scattering matrix for these mesons is strongly constrained by integrability, which implies, in particular, the absence of particle production and factorization of the multi-particles amplitudes into the product of the two-particle scattering. These requirements plus the conditions of crossing invariance and unitarity are so strong that allow one to compute the S-matrix exactly. The two-particle S−matrix for the O(N ) sigma-model has been found by Alexander and Alexey Zamolodchikov in their seminal paper [13]. It has an explicit form S kl ij (θ) = δ ij δ kl S 1 (θ) + δ ik δ jl S 2 (θ) + δ il δ jk S 3 (θ), S 3 (θ) = S 1 (iπ − θ), S 1 (θ) = − 2iπ (N − 2)(iπ − θ) S 2 (θ), S 2 (θ) = Q(θ)Q(iπ − θ), (1.6)