Mitchelstown were 0-5 to 0-3 down in the 20th minute when Seamus Harnedy extended Glenbower’s lead to two.
Glenbower, whose midfielder Kieran Lane top-scored with 0-5 (four frees), were without talisman Joe Deane and crucially failed to score for a 27-minute period thereafter.
In contrast, Mitchelstown registered six points in that period as Beston, scorer of 0-5 — hit three excellent points from open play and Michael Walsh, Jason Cott and Shane Cahill also raised white flags.
That allowed Mitchelstown lead 0-9 to 0-5 before Lane scored two points with just six minutes remaining.
Still, Beston and Patrick Molloy guaranteed Mitchelstown’s passage prior to Lane’s consolation score.
Scorers for Mitchelstown: S Beston (0-5, 2fs), J Sheehan, D Dineen, M Walsh (f), J Cott, S Cahill, P Molloy (0-1 each).
Scorers for Glenbower Rovers: K Lane (0-5, 4fs), D Cahill, S Lyons, S Harnedy (0-1 each).
MITCHELSTOWN: L Hanna; S Coughlan, F Herlihy, M Maher; O Burke, S Fox, P Molloy; L Flynn, D Dineen; M Walsh, S Beston (capt), J Cott; J Sheehan, S Cahill, J Finn.
Subs: A O’Brien for Sheehan (44), J O’Sullivan for Finn (60), P Donegan for Cott (61).
GLENBOWER ROVERS: S Scully; T Murphy, P McGrath, A Keniry; C Murphy (capt), C O’Brien, J Dullea; S Harnedy, K Lane; C Fogarty, S Lyons, B Collins; S Long, D Cahill, J O’Connor.
Subs: B Barry for McGrath (20), S Murphy for O’Connor (ht), J Kelleher for Fogarty (46), M Murphy for Keniry (49), A Keniry for T Murphy (54).
Referee: James Dorgan (Nemo Rangers).