A double from Dom Heaume clinched the Muratti Vase for Guernsey as they beat Channel Islands rivals Jersey 2-0 at Springfield.
Heaume sent the visitors on their way to victory when he netted following a well-worked corner after 27 minutes.
Jack Boyle went closest for Jersey but his dipping effort was tipped over by back-peddling keeper Chris Tardif.
Heaume doubled Guernsey's advantage with his glancing header just before the hour mark to seal victory.
"It was a phenomenal performance from a phenomenal group of individuals," said Guernsey manager Kevin Graham. "I just have confidence in this group.
"I'm incredibly proud and these boys are green through and through."
It was the first time since 2006 that a side had scored more than once in a Muratti final.
"Congratulations to Guernsey, they got their tactics spot on today," said Jersey boss Craig Culkin.
"I'm disappointed I think with our application, our energy levels and our commitment which is not normally the case.
"I think we need to learn from that but I don't think we can have any complaints about the result."