A sealing assembly for a fluid infusion device includes a base plate, a reservoir port receptacle, a flow base component, and a needle sealing element. The receptacle receives the reservoir port, and has proximal and distal ends, and a needle entry in the distal end to receive a hollow needle of a fluid reservoir. The flow base component has an inlet structure defining a fluid chamber, and a needle guide pin protruding therefrom. The end of the guide pin fits within the hollow needle. The needle sealing element has a proximal flange adjacent to the inlet structure, a distal flange opposite the proximal flange, a neck section between the flanges, and a needle opening extending through the neck section. The needle sealing element is positioned within the port receptacle such that the neck section surrounds the end section of the needle guide pin.