Celtic and Ness contested the first of the Highland Fuels semi finals on an unusually perfect night for football at Harbison Park.
Both teams were at near-full strength and served up a classic encounter with the south end men edging through thanks to a dominant first half performance.
After an even start, it was actually Celtic who opened the scoring when a long ball forward from Joel Bradley was latched onto by James Aitken who finished past Duncan in the Ness goal.
The early goal seemed to spur Ness into life however, in particular James Farmer who was untouchable for large spells of the opening period, and it wasn’t long before they were back on terms when Stuart Copland smashed home a loose ball in the box.
Copland then added to his tally from the penalty spot, after Bradley was adjudged to have tripped Farmer in the box at the end of another swashbuckling run.
Celtic continued to threaten on the break with youngsters Kennedy Moar and Shane Odie looking dangerous in the wider areas but several corners and pop-shots from range came to nothing.
And Farmer wasn’t finished his first half’s work yet, the dynamic midfielder slotting home a third goal after Celtic gave the ball away high up the pitch.
Celtic made a couple of changes in the second half, with Ellis Smith and the pacy Brendan Johnson added to the fray in an attempt to turn things around for the town side.
And the changes paid dividends 10 minutes into the half and a looping ball deceived the Ness back line, and Johnson nipped in at the back post to prod the ball home for 3-2.
Celtic pushed for the equaliser with Tom Moncrieff getting in behind on a couple of occasions and Aitken from range forcing Duncan to tip around the post.
With just 10 minutes left on the clock, Ness got their all-important fourth goal. A defensive mix up allowed the ever-willing Ian Bray to nick the ball of Kieran Glaser in the Celtic goal and slot the ball into the empty net.
To Celtic’s credit, they pulled a goal back in the dying minutes when another long ball forward from Smith was delightfully controlled and swept home by Aitken for his second of the match.
But it was too little too late and Ness booked their spot in the first cup final of the season where they will face either Scalloway or Thistle on Monday 15th April.
CELTIC TEAM: K Glaser, J Bradley, J Clubb, R Grant (E Smith), R Smith, C Regan, J Aitken, T Moncrieff (S Regan), S Odie, S Orlowski (B Johnson), K Moar (B Buggy)