Instonians failed with their bid for promotion at the European Club Championship series in Milan yesterday, going down 3-1 to unfancied Gibralter side, Eagles.
Needing only a draw to reach today's final and obtain their objective, the Ulster side looked to be well on course when Paul Hollway gave them the lead from a 41st minute penalty corner.
However, Eagles earned promotion to the top flight for the first time when they scored three times in the final 20 minutes after Instonians failed to capitalise on their territorial supremacy.
Today, the Ulster and All Ireland champions will face Glasgow Western with bronze medals at stake. On Saturday, Neil Cooke scored a hat-trick in an 8-0 win over Stockholm, the other goals coming from Julian Lewis, Mark Irwin, Mark Wainwright, Paddy Brown and John Atkins.