Paddy Herrity and Niall Murphy led the way as Summerhill College booked a spot in the final. The pair hit 1-10 between them, with Herrity's first-half goal setting up a clash with St Jarlath's of Tuam in next month's decider.
Summerhill led by 1-8 to 0-3 at the break after taking over proceedings when Mary's raced into a two-point lead in the opening minutes. However, four frees on the bounce and Herrity's goal gave the Sligo side the upper hand. James Casserley kicked a point from play for Mary's just after the break, but they were unable to pull any closer and substitute Paul Logan's late free sealed the result.
Scorers -- Summerhill: P Herrity 1-5 (5f), N Murphy 0-5 (1f), C Finneran, P Logan 0-1 each. St Mary's: C O Laoi 0-3 (3f), M Upton, C O Conaire, E Walsh, J Casserley, F O Bearra (1f) 0-1 each.
Summerhill -- V Cadden; E Flanagan, D Burke, C McDonagh; C Doherty, B McGarry, M Flynn; N McManus, K Sweeney; C Finneran, H Cawley, D Long; S Cawley, N Murphy, P Herrity. Subs: P Logan for H Cawley (35), S Peyton for McManus (42), M Casey for Long (44), T Finnegan for McDonagh (53), N McManus for Flanagan (62).
St Mary's -- R Lavelle; B McEntee, B Madden, M O Bearra; M O Curraoin, E Walsh, B Bohan; J Doran, M Mulkerrins; J Casserley, F Ó Bearra, C Ó Conáire; C Gleeson, C Ó Laoi, M Upton. Subs: D Kerr for O Curraoin (22), T Ward for Bohan (41), A O'Toole for O Connaire (60), C McMahon for McEntee (60), D Higgins for Madden (66).
Ref -- E McAndrew (Mayo).