Early pressure from the Ardee men saw them race into a two point lead.
The Dromiskin side had Alan McKenna to thank for an opening score.
Yet the home side looked composed throughout the opening half.
While an early Alan Kirk goal seemed to have killed off the away sides chances up stepped Robert Samson to hammer home two goals in the space of a minute to leave the margin at just three points.
That mini revival was put to bed by David Woods when he gave Eamonn Neary in the Joes goal no chance with a blasted shot.
St Mary’s now progress in to the Quarter finals of the Sheelan Cup.
St Marys: Dwayne Crosby; Niall Carroll, Paul Malone, Barry Faulkner; David Woods (1-0), RJ Callan, Jamie Rooney; Robbie Leavy, Donal Matthews (0-1); Fergal Diamond (0-1), Dean Matthews (0-1)Mark Gorman; Paudie Clarke (1-2), Alan McKinney (0-2), Alan Kirk (1-3). Subs- Mark Fay for Mark Gorman, Shane Carroll for Alan Kirk, David Rooney for David Woods, John Bingham for Donal Matthews.
St Josephs: Eamonn Neary; Chris Brennan, Bernard Mulligan, David Mernagh; Phillip Kinahan, Anthony Keenan, John McGuinness; Peter Mulligan, Peter Brennan; Aaron Smyth, Alan McKenna. Jack Mulligan; Damien Connor, Robert Samson (2-0), Lorcan Doyle. Subs- Conor Lynch for Anthony Keenan, Alan Lynch for Jack Mulligan, Alan Quigley for Aaron Smyth.