Conditions were perfect and Athletic immediately took the game to the home side, with Rose and Reid having good attempts well saved by the keeper.
After 15 minutes, Monymusk were incensed when two bookings in quick succession for dissent led to an early bath for their midfielder, and reduced the side to 10 men.
Athletic quickly capitalised and after good work from Reid, Mitchell hammered home from eight yards out to put the visitors in front.
This delighted the large travelling support.
However, the home side fought back and equalised just before half time.
The second half continued to be evenly matched with both sides having chances but a rare goal from Hendersn put Athletic back in front.
His long-range shot from 25 yards deceived the keeper and flew into the top corner.
The visitors then took control and looked to add to their score.
McLean and Forrest replaced Reid and Stephen and the fresh legs sealed it for Athletic. First, Forrest headed home McLean's pinpoint cross after 65 minutes and with 10 minutes to go, McLean again sent over a perfect cross and Forrest scored a second to secure the victory.
Athletic had several chances to increase their tally but settled for four.
It was a great all-round performance which brought the season to a successful conclusion for management team Graham Cameron and Graham Wark.
Their tireless efforts brought home a league and cup double for the first time.
Team: Anderson, Bowron, Henderson, M Campbell, Wright, Milne, Stephen, Gellatly, Rose, Mitchell, Reid. Subs: Forrest, Ross, McLean, A Campbell, Alexander.