A piston pump includes a piston assembly having at least one cross bore and a longitudinal bore corresponding to the at least one transverse bore, a cylinder, into which the piston assembly is guided in a longitudinally movable manner, and an inlet valve with a cage element, in which an inlet valve spring and an inlet valve sealing element are disposed, and a corresponding inlet valve seat, which is disposed on the piston assembly. Fluid flows through the longitudinal bore into a compression chamber via the inlet valve. A return spring is disposed in the compression chamber. The cage element has a resilient high-pressure sealing element that is configured to receive radially acting power components, and to effect a seal against a cylinder wall via a radial sealing surface, and in order to effect an axial seal against the piston assembly via an axial sealing surface.