Quantum coherence is detected in the 4f single-ion magnet (SIM) Yb(trensal), by isotope selective pulsed-EPR spectroscopy on an oriented single-crystal. At X-band, the spin-lattice relaxation (T1) and phase memory (Tm) times are found to be independent on the nuclei bearing, or not, a nuclear spin. The observation of Rabi oscillations of the spin-echo demonstrates the possibility to coherently manipulate the system for more than 70 rotations. This renders Yb(trensal), a sublimable and chemically modifiable SIM, an excellent candidate for quantum information processing.