All of the scoring took place in the first half, with Narberth fullback Daniel Mason drawing first blood when he crossed for an unconverted try after three minutes.
Fishguard outside-half Mark Waddupp clawed back three points with a penalty, but the Otters pushed further ahead with an unconverted try by hooker Owain Williams.
Both teams were playing at a fast and furious pace. Mark Waddupp scored a try for Fishguard near the posts, but the Otters went back in front after a long distance try from centre Sion Gage.
A try by Mark George just before half-time brought the visitors within two points of the Narberth score.
Both teams continued to play in the same vein in the second half, but the defences held firm to prevent any further scoring.