Currently, all-in-one flexible supercapacitors have achieved great attainment, but their intrinsic weak physical interfacial interactions inevitably lead to interfacial fatigue debonding during violent and long-term deformations. Herein, a controllable interfacial molecular level entanglement strategy (CIMES) is proposed to design and build such highly flexible and mechanical robust asymmetric supercapacitors (FASCs) with all-in-one configurations. The controllable interfacial molecular level entanglement is achieved by controlled solvent induced re-entanglement and alcoholysis of the electrolyte homogeneous matrix - ethylene vinyl alcohol (EVOH) copolymer. With the generated electrolyte-philic and electrolyte-proof matrix and all-in-one configuration of anode/electrolyte/cathode used in the FASCs, low interfacial charge transfer resistances, good mechanical properties, and high interfacial peeling strength are achieved simultaneously. Thus, the all-in-one FASCs exhibit a much higher areal capacitance, superior cyclic stability, and unprecedented mechanical durability with capacitance retention of 100.6 % and 100.7 % exceeding 10 000 bending and twisting cycles respectively. Furthermore, the all-in-one FASCs are demonstrated to work under bending, twisting, and even folding conditions. Those findings can provide a new platform on the design of all-in-one configurations for the FASCs with superior mechanical durability, highly desired for many flexible devices such as geotextiles.