GHA had not lost at Braidholm for a number of months, but nothing was going to stop the men from Troon being crowned BT National League Division One champions.
Marr came out on top 39-22 to lift the second tier trophy and the jubilant scenes at the end from players, committee members and supporters showed just how much it means to the Fullarton Park outfit.
A few years back they were in the West regional leagues, but strong leadership from president Kevin Quinn, head coach Craig Redpath and a young, enthusiastic bunch of players has seen them climb the levels rapidly.
Last season they were beaten to the title by Watsonians and then lost out to Gala in the promotion/relegation play-off, but this year they have led the way for the majority of the campaign.
Yesterday they took an early lead at GHA thanks to a penalty by Colin Sturgeon. Stephen Adair added an unconverted try to make it 8-0 before GHA got on the scoreboard with a penalty.
Three more tries before the break saw Marr place one hand on the trophy.
Conor Bickerstaff, Adair and William Farquhar went over and it was 27-3 at the interval.
GHA fought back in the second half, but further tries from Gregor Paxton and Scott Bickerstaff saw Marr come out on top.
Edinburgh Accies finished second after a 60-10 win at home to Aberdeen Grammar and the Raeburn Place men will now take on Hawick in the promotion/relegation play-off later this month.