Drogheda United 0 Glentoran 1
Glentoran finished with nine men and also survived a penalty as they ended cash-strapped Drogheda's two-year grip on the Setanta Sports in dramatic fashion at United Park tonight.
Glens now meet either Derry City or Cork City in the final on November 1.
Unbeaten this season and top of the Irish League, Glens had the ideal start with what proved a gift of a winner after just three minutes.
Though Jason Hill fell over after cutting past Shane Robinson on the left, the Glens winger was quick to his feet and his low shot squirmed through the body and legs of an embarrassed Jamie Ewings.
Drogheda finally had the chance to draw level on 74 minutes when Glens' skipper Paul Leeman was sent off for hauling down Drogs' captain Declan O'Brien.
But Paul Keegan blasted his penalty off the bar.
Glens then had match-winner Hill sent off for a second booking on 89 minutes for a foul on Robinson.