The preliminary idea of statistical weighted B-summability was introduced by Kadak et al. [27]. Subsequently, deferred weighted statistical B-summability has recently been studied by Pradhan et al. [38]. In this paper, we study statistical versions of deferred weighted B-summability as well as deferred weighted B-convergence with respect to the difference sequence of order r (> 0) involving (p, q)-integers and accordingly established an inclusion between them. Moreover, based upon our proposed methods, we prove an approximation theorem (Korovkin-type) for functions of two variables defined on a Banach space C B (D) and demonstrated that, our theorem effectively improves and generalizes most (if not all) of the existing results depending on the choice of (p, q)-integers. Finally, with the help of the modulus of continuity we estimate the rate of convergence for our proposed methods. Also, an illustrative example is provided here by generalized (p, q)-analogue of Bernstein operators of two variables to demonstrate that our theorem is stronger than its traditional and statistical versions. 1. Introduction, Preliminaries and Motivation Let ω be the set of all real valued sequences and call any subspace of ω the sequence space. Let (x k) be a sequence with real or complex terms. Suppose ∞ is the class of all bounded linear sequence spaces and let c, c 0 be the respective classes for convergent and null sequences with real or complex terms. We have, x ∞ = sup k |x k | (k ∈ N), and we recall here that under this norm, the above mentioned spaces are all Banach spaces. The space of difference sequence was initially studied by Kızmaz [30] and then it was extended to the difference sequence of natural order r (r ∈ N 0 := {0} ∪ N) by defining λ(∆ r) = {x = (x k) : ∆ r (x) ∈ λ, λ ∈ (∞ , c 0 , c)} ;