Jersey director of rugby Harvey Biljon says his side must look at their attitude after their surprise
It was the first time Plymouth had won since March, having twice been beaten by Jersey in the previous six weeks.
"We spoke before the game and said it would be interesting to find out how far this group of players has come with regards to our professional attitude.
"We have to address it because we don't want complacency to creep in," he said.
Despite the loss Jersey are still second in their British & Irish Cup pool but must win their final two games to have a realistic chance of making the knockout stages.
"We didn't put in the performance that we've been used to this season," Biljon told BBC Radio Jersey.
"It's a difficult one to take, but one we've got to learn from pretty quickly.
"We had our opportunities to get ourselves back into the game, we didn't take all those on offer.
"I think one of the key aspects of the game was the fact that there were more unforced errors in this game than we've had in any game all season."