Searching for superconductivity in single element with high Tc is of great interest both for fundamental science & potential applications due to the easy recipe. It is especially interesting to explore high Tc superconductivity in transition metal elements wherein the conventional BCS theories suggest that d electrons are not favorable to form high Tc superconducting state. Here we report discovery of surprisingly robust superconductivity up to 310 GPa with almost constant Tc above 20K in a wide pressure range from 108GPa to 240 GPa in titanium. The maximum Tconset above 26 K and zero-resistance Tczero of 21 K are record-high values hitherto achieved among elemental superconductors. This finding is in sharp contrast to the theoretical predications based on the pristine electron-phonon coupling scenario. Measured normal state conductivity reveals significant s-d scattering. Quantum calculations show strong s-d transfer and d-band dominance, indicating correlation driven contributions to the robust high-Tc superconductivity seen in dense titanium. Different from most high-Tc superconductors that are either complex ceramic or intermetallic compounds, titanium metal is much easier to process and hosts notably higher and more robust Tc and critical magnetic field Hc compared to the widely used superconducting NbTi alloy. This study opens a fresh promising avenue for rational design and discovery of high-Tc superconductors among simple materials via pressure tuned unconventional mechanism.