Hillside started this Links Park contest well and Fordoun could hardly leave their half in the opening exchanges.
However, in the ninth minute Fordoun won a free kick which Kevin Hector floated into the box where James Mennie sent a looping header over the home keeper and celebrated his seventh goal of the season.
The Galaxy added to their lead in the 21st minute when Michael Deans back-heeled the ball over the line from two yards out. The ginger winger had promised a hat-trick pre-match and he was on course to achieve just that when he made the score 3-0 after latching on to a wayward Dean McComiskie shot and finishing well.
Hillside forced David Jamieson into a good save after number seven rampaged down the left wing and cut into the box before getting his shot away.
On the stroke of half time, Fordoun were dealt a blow when a crude challange saw Michael Deans forced from the field because of what was later proven to be ligament damage.
HT Hillside 0-3 Fordoun Galaxy
Four minutes into the second half Hillside grabbed a lifeline when they won a penalty which was cooly dispatched into the bottom corner.
They would have had a second in the 56th minute but for a wonderful reaction stop from David Jamieson who pushed the ball over the bar.
Craig Thomson came close to restoring Fordoun’s three-goal cushion when Dean McComiskie played him in but the home keeper made a good save.
Thomson did score on the hour mark when he latched onto a lovely Kevin Hector pass and dinked the ball over the Hillside number one.
The lead was cut to two again when Hillside scored a third and, with nine minutes remaining, they got a third to make for a nervy finale.#
Fordoun held on for the win which continues their run of being undefeated in local cup competitions this season.
Fordoun: Jamieson; A Stirling; Mennie; R Deans (Anderson); Cuthill; Hector; R Stirling; Thomson; L Cruickshank; M Deans (Henderson) (Davies) & McComiskie.
Results from Sunday March 2
MCT 1-3 St Cyrus
The Old Bolag 2-2 Northern Vaults
Matrix Cup Quarter Finals
Bervie 1-11 Hudsons
Fettercairn 4-0 Marykirk
Golf Inn 8-2 Lochside United
Hillside 3-4 Fordoun Galaxy
League fixture for Sunday March 9 (10:45ko)
@Bar FC v St Cyrus
Bervie v Hudsons
Fettercairn v Hillside
Fordoun Galaxy v Lochside United
Marykirk v MCT
The Old Bolag v Golf Inn