After McNeice reduced Glenties' lead to the minimum, the advantage was suddenly four points when Gallagher blasted emphatically to the net on 18 minutes.
Anthony Thompson knocked over a couple of frees for Glenties, for whom young Darragh Gallagher scored an excellent point at the start of the second period.
Another Dara Gallagher point restored Glenties' lead before half-time but despite their dominance, it was only a one-point game and there was that suspicion that, on the scoreboard at least, Naomh Conaill had not fully exploited their superiority.
Keeper Curran ran up the field on two occasions in the dying seconds to attempt long pot-shots from 45 metres but he failed to find the target both times as Glenties set up their provincial decider appearance against Crossmaglen.