They were always the better side but had to withstand a late rally as the Donegal champions came from four points down to almost snatch a draw in the closing minutes.
The sides were level 0-4 each at the interval, with Glenswilly’s Neil Gallagher hitting two points.
Latton again enjoyed superiority on the restart and a post denied them a goal when Stephen McElroy was clean through. But thanks to the industry of Shane Coyle, they were 0-10 to 0-6 ahead with ten minutes left.
Michael Murphy, showing signs of fatigue from his trip to Australia, started the Glenswilly comeback and Joe Gibbons and Brian Farrelly also added points to set up a nerve-jangling end. Farrelly had claims for a foul with the last attack but referee Barry Cassidy waved play on.
Latton face Down champions, Burren, in the Ulster semi-final.
GLENSWILLY: P O’Donnell; R McDaid, E Ward, R Crawford; J Gibbons (0-2), J P McDaid, B McDaid; G McFadden (0-1), N Gallagher (0-2); K McFadden, C Bonner, C Kelly (0-1); D McGinley, M Murphy (0-2), L Kelly.
Subs: J McFadden for L Kelly 40; B Farrelly (0-1) for C Kelly 42; B Molloy for B McDaid 49; M McGinley for K McFadden 53.
LATTON: S Farmer; P Fitzpatrick, E Lennon, O Coyle; S McElroy, K Duffy, S Fitzpatrick (0-1); O Lennon (0-2), A Farmer (0-1); N Traynor, O Duffy (0-1), P Shannon; S Coyle (0-3,1f), H McElroy (0-2,1f), B Lennon.
Sub: P Shannon for B Lennon 49.
Referee: B Cassidy (Derry).