Arrowtown now has the chance to win more silverware when it plays Lawrence in the countrywide final this weekend.
Upper Clutha opened the scoring when first five-eighth Byron Clarke slotted a penalty goal in the sixth minute, and for the first 15 minutes the visiting side appeared to have the edge.
A Willie Scurr intercept try from his own goal-line pushed the score out to 8-0.
Arrowtown's first points came from the reliable boot of first five-eighth Reece Winter, who knocked over a penalty following an indiscretion from the Upper Clutha forwards at a ruck.
Upper Clutha controlled the match for most of the first half but could not convert possession into points.
Just before half-time, Winter kicked his second penalty goal after a late hit advanced his team into a kickable position, making it 8-6 to Upper Clutha at the break.
The tide turned the home team's way in the second spell.
Three minutes into the half, Winter slotted his third penalty of the match to take his side into the lead.
Ten minutes later, Arrowtown scored its first try after building several phases and allowing dynamic No 8 Dan Iosefo to drive his way over the line.
Winter gave the crowd even more to cheer about he when he successfully rushed the conversion attempt from the sideline after the ball had fallen off its tee.
Two minutes later, Arrowtown, with its tail up, crossed for another try, to openside flanker Aidan Winter, in much the same fashion as the first.
Reece Winter added the extras and the score bulged out to 23-8.
Upper Clutha was not done, though, and it scored the try of the match in the 70th minute when winger Scurr broke Arrowtown's defence out wide and scampered 50m before offloading to fullback Ben Purvis, who went across untouched to close the gap.
The score did not change after that, and while the visitors had plenty of possession they were guilty of kicking too much of it away.
The back three, Purvis in particular, were the stand-outs for Upper Clutha, while stalwarts Aidan Winter and Iosefo were the pick of the Arrowtown players, providing leadership and forward momentum.
