The Islanders finished 6-2 up against Gibraltar in the final game in Group B, having traded goals with their opponents in the opening ten minutes.
With both sides losing to group winners Isle of Man earlier in the tournament the game was crucial in deciding who would retain their medal hopes.
The winners would join the Manx women in the semi-finals and book a tie against Group A winners Ynys Mon, and Jersey stunned their rivals early.
Megan Wood fired home from range with just 30 seconds gone, although the advantage didn’t last long. Shania Robba levelled the scores inside eight minutes.
Jersey maintained their presence in attack as the first half progressed and they were rewarded before the break. Natasha Keen slotted home for 2-1 and Wood doubled her tally from a tight angle.
Jersey had one foot in the last-four and captain Jodie Botterill and Eve Watson added further weight to that stance with long-range strikes. Rosie Corbett added a sixth before Gibraltar pulled one back.
They will meet Ynys Mon in the semi-finals tonight (6.30pm).
Jersey Women: Sara Luce (Amy Tierney 85), Lauren Quémard (Daisy Jackson 85), Ciara Giles, Sophie Botterill, Tiffany Sundby, Libby Barnett, Holly Muirhead, Eve Watson, Natasha Keen (Abi Scandrett 72), Jodie Botterill (Rosie Corbett 75), Megan Wood (Sam Silva 72).
