Drogheda 0 Cork City 2: Not for the first time an encounter between these sides saw the referee brandish a red card as Drogheda finished with 10 men with the sending off of goalkeeper Dan Connor 13 minutes from time.
A goal in either half saw Cork top the table and ensure a home semi-finals draw.
Cork took the lead after 13 minutes when Denis Behan's speculative drive from 25 yards edged past the fingertips of Connor and in off the post.
Chances were few and far between, until Connor took centre stage. With 77 minutes gone, he caught the ball on his line, and as Behan raced in to face the Drogheda net-minder he pushed the ball into the Cork forwards face.
Referee Mark Courtney produced the red card immediately and Drogheda withdrew Glen Fitzpatrick to be replaced by reserve goalkeeper Charles Tracey.
The new man's first task was to pick the ball from the back of the net as George O'Callaghan fired home the spot kick.
DROGHEDA: Connor, Lynch, Webb, Gray, Whelan, Fitzpatrick, Bradley, Tyrrell, Ristila, Williams, Leech. Subs: Robinson for Williams (51 mins); Barrett for Leech (57 mins); Keegan for Ristila (72 mins); Treacy for Fitzpatrick (78 mins).
CORK CITY: Devine, Murphy, Murray, O'Brien, Fenn, O'Callaghan, Woods, Lordan, Gamble, Behan, Horgan. Subs: Softic for O'Callaghan (84 mins); McNulty for Devine (86 mins); Nolan for Behan (88 mins).
Referee: M Courtney (Dungannon).