  We demonstrate fast universal electrical spin manipulation with inhomogeneous
magnetic fields. With fast Rabi frequency up to 127 MHz, we leave the
conventional regime of strong nuclear-spin influence and observe a spin-flip
fidelity > 96%, a distinct chevron Rabi pattern in the spectral-time domain,
and spin resonance linewidth limited by the Rabi frequency, not by the
dephasing rate. In addition, we establish fast z-rotations up to 54 MHz by
directly controlling the spin phase. Our findings will significantly facilitate
tomography and error correction with electron spins in quantum dots.
