Incorporating superconductors in terahertz metamaterials potentially provide unprecedented control over resonance features which has huge implications in the real-world technologies. In this work, we reveal an extremely sensitive Fano resonant high-Tc superconducting metamaterial fabricated using ion irradiation (II) technique which shows all-optical, ultrafast, switching and modulation of the sharp Fano resonances at extremely low optical pump fluences. The ultrasensitive nature of this metamaterial system is attributed to the presence of a dielectric material (non-superconducting YBCO) in the split gaps, which thus results in the large field confinement in the subwavelength resonant structure. © 2019 IEEE.