GAA: Des wins it for Fianna!; Na Fianna 1-13 St Brigid's 0-12.
Until Mackin struck this had been a very close game, with Brigid's well in it thanks to a great display from Declan Darcy, who finished with 0- 9 beside his name.
The goal came about when Dessy Farrell's long point effort fell short which allowed Mackin to rise above his marker and fist home.
Mackin was selected at midfield, but he found himself up front in a team which contained 13 positional switches to the one named in the programme.
Brigid's captain David Fitzgerald got the first score of the day from a free, but as soon as Farrell equalised Na Fianna dominated.
They picked off some great scores courtesy of Karl Donnelly, Ian Foley and Mackin to move into a comfortable 0-4 0-1 lead after 12 minutes.
Brigid's finally clicked into gear on the quarter hour so they had to rely on Darcy's free kicking excellence to pull them back level. His four points in the first half helped leave it 0-5 apiece at the break.
NA FIANNA: S Gray, S McGlinchy, B Quinn, T Lynch, M Foley, K McGeeney(0- 1), P McCarthy, S Forde, D Mackin (1-1), M Galvin (0-4), S Connell, J Sherlock, D Farrell (0-1), K Donnelly (0-1), I Foley ()-3). Subs: D Keegan (0-1) for S Forde; A Shearer for D Mackin.
ST BRIGID'S: C Boyle, M Cahill, Declan Cahill, K Nolan, P Andrews, Dermot Cahill, K Keane, K Darcy (0-1), J Ward, C Kilmurray, D Darcy (0-9), C O'Muircheartaige, D Fitzgerald (0-1), C McGlynn, K Kilmurray (0-1). Subs: P Molloy for C McGlynn; K Kehilly for D Fitzgerald.