The first Deeside Derby of the season went to form as Culter left Milton Park with the three points.
The Deesiders went well clear at the top of the Superleague table after a resounding win against a young, but spirited, St Ternan side.
With champions Hermes losing at home to Dyce the result was all the more pleasing for the Leuchar Loons who are now eight points clear of second place Dyce.
Saints, however, are rooted to the bottom of the league and will have to quickly improve if they are to avoid a relegation battle.
The match was in doubt until the kick off, due to frost, but the referee let it go ahead once the gritters had been out.
Saints, fighting for their top league survival, had the first chance but this only troubled the Crathes Burn.
Culter then had a great chance but the Saints keeper saved with his left foot from an Allan Youngson attempt.
The opener was not long in coming when McArthur sent in a delightful cross which Jamie McAllister gleefully turned home.
A few minutes later Pyper struck a free kick for the Saints but Neil Duffy saved easily.
McAllister then set up Youngson but the enigmatic midfielder blasted well over before a decent effort from Ian Leith was hoofed off the line.
The second, however, was not long in coming and this time McAllister turned provider when he set up Mike Taylor who fired a brammer into the roof of the net.
Saints were on their heels even at this early stage as they tried to stem the onslaught and the ‘keeper had to produce an outstanding save to deny McAllister but moments later a deep Youngson cross was met by Dod McBain who slid the ball home from close range.
It was all over bar the shouting when a move of the highest quality found Ian Leith who fired a peach off the underside of the bar and into the net.
The Deesiders went nap towards the end of the half when an a Youngson free kick was saved but McArthur was on hand to thunder the loose ball into the net.
The second period was barely five minutes old when slack marking by the home side allowed Taylor to rise and power home a header from a Youngson corner.
The Saints ‘keeper was once again the hero when he pulled off a spectacular save from a Youngson attempt.
Both sides then sent on substitutes and the match went into hibernation for long spells but Culter made it seventh heaven in the 73rd minute when Taylor fired in a penalty for his hat-trick.
This weekend, Banchory host Stonehaven (1.30pm) in the Superleague while Culter welcome Maud to Crombie Park in the second round of the GA Engineering Inter Regional Cup (1.15pm).