Milngavie started the game brightly, taking the game to Ardencaple and forcing two saves from the Caple keeper.
However, Milngavie deservedly took the lead when a defence splitting pass was knocked home by their centre forward.
The opening goal seemed to bring Ardencaple to life and after 20 minutes they created two golden opportunities which were narrowly spurned by Ross.
Caple were made to pay for the missed chances when the dangerous Milngavie striker outpaced the Ardencaple defence to slot home his second goal of the match.
Things went from bad to worse for Ardencaple shortly before half time when Milngavie bundled home a third goal.
The Ardencaple youngsters got off to the perfect start at the beginning of the second half when Ross coolly chipped the keeper to reduce the deficit to 3-1.
Ross ensured a thrilling ending for the match when he drilled home a second for Ardencaple with 15 minutes still on the clock.
Ardencaple pushed for an equaliser but could only muster a series of half chances as time run out on their cup dream.