Reds suffer disappointing defeat at St Peter
It was, without doubt, the Islanders' worst performance of the season so far, and the 23-14 reverse means that the chance of Jersey making the quarter-final stages for what would be the first time in the club's history now look very slim.
However, having secured their first win of what's been a disappointing season, Plymouth will hope Friday's triumph will ignite their league campaign and drag them free of the single Championship relegation spot.
The visitors started the better and returning fly-half Declan Cusack converted an early penalty to put the south coast club ahead. Moments later, Eoghan Grace crossed the white wash to put his side 10-0 up after Plymouth had run the ball from inside their own half.
Cusack added another successful penalty before a Jersey clearance from their own try line was charged down and fell kindly to Neale Patrick, who scored his team's second with fewer than 25 minutes played.
Searching for their first points, Jersey had a period of pressure in the final ten minutes but errors at key moments prevented the Reds from scoring.
It was Plymouth who finished with a flourish and, but for some last ditch tackling on the Jersey try line, they may have added to their tally.
At 20-0 down, the hosts needed something special in the second period and, although there was a marginal improvement, they couldn't claw back the deficit.
Both sides missed penalties before winger Grant Pointer got Jersey's first try with just under half an hour to go.
The Islanders were unable to build on that score and Plymouth extended their lead with another converted penalty from Cusack.
With time running out, replacement flanker Nick Haining scored Jersey's second try but it was too little too late as his team failed to take a single point from the match.
Leinster play Carmarthen Quins in Dublin on Saturday.
Pictures: David Ferguson.
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