James Keddy's stunning first goal for Drogheda proved to be the winner as Paul Doolan's men beat Linfield 1-0 at Windsor Park to book a Setanta Cup final date with Cork City.
Linfield had a third minute Peter Thompson strike disallowed for a foul on keeper Charlie Treacy, making his full Drogheda debut.
The FAI Cup holders dominated the first half and took the lead in the 33rd minute when substitute Mark Leech released Keddy who fired home from 25 yards.
Linfield only threatened through set pieces and Drogheda's Glen Fitzpatrick could have had a hat-trick either side of half-time. Top scorer Paul Keegan was also unlucky not to get on the score sheet.
Glenn Ferguson and Michael Gault had late chances for Linfield but young Treacy denied them with two fine saves.