Brigg made the opening attack but the home keeper Alex Wyatt-Ingram collected the ball confidently after it had been played in from the left wing.
A free kick from outside the penalty area by Martin Pembleton was just wide of the goal and at the other end of the pitch the first Armthorpe attacking threat was headed clear.
The opening minutes continued to be hectic with open play at both ends of the pitch but it was the home team who scored the first goal after twelve minutes of play. The ball was delivered from a midfield free kick and temporarily cleared but was driven back in from the left wing to fall for Louis Wardle to drive it into the bottom corner from twenty-odd yards out.
Brigg responded well with some neat inter-passing moves from Pembleton, Steve McCarron and Scott Phillips, but several golden opportunities to score before half time were squandered which ultimately proved costly.
Tom Collins made a couple of good diving saves to keep the score to 1-0 at the break.
The second half began well with a more determined Brigg team levelling the score four minutes in when Pembleton controlled a pass from the left and hooked a volley on the turn past Wyatt-Ingram.
Brigg’s best spell of the game continued as they took the lead on fifty-five minutes when Conner Harman headed home Finley O’Sullivan’s in-swinging cross.
The home team then rallied to test out the Brigg defence but Collins made a smart stop from Jamie Austin, then James Petronzio cleared a goal-bound header off the line.
Armthorpe’s pressure paid off and they equalised on seventy-five minutes, Austin heading in from Rhys Plater’s corner.
The home team scored the winning goal three minutes from time when an unmarked Austin met another long throw-in from the left by Owen Sykes to head past Collins and confine Brigg to their second league defeat of the season.