We demonstrated the resistive random-access memory (RRAM) characteristics in cost-efficient, single-step, and in-situ grown nanostructured mixed-phase CuxO (x = 1, 2) thin films, on a commercially available Cu sheet, fabricated using thermal treatment under ambient conditions. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements explain the surface morphology of grown mixed-phase CuxO thin film with substrate imprints. Fourier-transform Infrared spectroscopy confirmed the mixed phase of Cu2O and CuO of synthesized thin films. The fabricated Al/CuxO/Cu RRAM device showed bipolar digital resistive switching followed by analog resistive switching. The device showed a fast-switching speed of 250 ms, high endurance durability for 2500 cycles, and better retention of 103 s, respectively. The interconnected CuxO with Cu sheet provides efficient charge carrier migration from the bottom electrode to the active layer. The formed defect and trapped site are responsible for the resistive switching behavior. Thus, the present study provides a way to harness the potential of RRAM on either thermally treated Cu sheets or realizing a Cu thin film followed by low-temperature annealing, which can easily be integrated into existing electronic devices for data storage applications.