Abstract: A fuel delivery system includes a connection assembly that reliably connects a high pressure fuel supply line to an inlet of a fuel rail. The connection assembly includes a fitting that decouples the retention function of the connection from the sealing function of the connection. The fitting is hollow and has a spherical leading end that is compressed against an inner conical surface of the fuel rail inlet to an extent that fuel rail material is displaced by the spherical leading end and a fluid-tight first seal is realized between the fitting and the conical surface of the fuel rail inlet. A weld is provided at a location spaced apart from the seal, the weld joining the fitting to the fuel rail inlet and retaining the fitting within the inlet in a compressed state, whereby the first seal is maintained.