We consider a class of quantum field theories and quantum mechanics, which we couple to Z N topological QFTs, in order to classify non-perturbative effects in the original theory. The Z N TQFT structure arises naturally from turning on a classical background field for a Z N 0-or 1-form global symmetry. In SU (N ) Yang-Mills theory coupled to Z N TQFT, the non-perturbative expansion parameter is exp[−S I /N ] = exp[−8π 2 /g 2 N ] both in the semiclassical weak coupling domain and strong coupling domain, corresponding to a fractional topological charge configurations. To classify the non-perturbative effects in original SU (N ) theory, we must use P SU (N ) bundle and lift configurations (critical points at infinity) for which there is no obstruction back to SU (N ). These provide a refinement of instanton sums: integer topological charge, but crucially fractional action configurations contribute, providing a TQFT protected generalization of resurgent semi-classical expansion to strong coupling. Monopole-instantons (or fractional instantons) on T 3 × S 1 L can be interpreted as tunneling events in the 't Hooft flux background in the P SU (N ) bundle. The construction provides a new perspective to the strong coupling regime of QFTs and resolves a number of old standing issues, especially, fixes the conflicts between the large-N and instanton analysis. We derive the mass gap at θ = 0 and gaplessness at θ = π in CP 1 model, and mass gap for arbitrary θ in CP N −1 , N ≥ 3 on R 2 .