We demonstrate an isolated phenomenon of soliton self-frequency shift over a bandwidth of 68.5 THz in the near-infrared spectral range. We designed, fabricated, and characterized a suspended core microstructured fiber made of highly nonlinear tellurite glass. The fiber is designed for a flat anomalous dispersion to leverage on Raman scattering-assisted frequency shift of a fundamental-order soliton. We demonstrate a prominent soliton with an input-power-based tunability in the spectral range from the 1560 nm central pump wavelength up to around 2400 nm central wavelength of the frequency-shifted soliton, when the fiber is pumped with 90 fs pulses from a commercial, fiber-based, mode-locked laser.