The home team had trailed for the whole match, having got off to a poor start, and was trailing 20-5 at the break.
But it came back into it and a couple of tries had it in touch as the clock wound down.
Arrowtown was caught with some hands in the ruck and Brodie Flannery had the chance to win the game. He slotted the penalty kick to clinch victory 27-25.
Veteran halfback Jai Baxter made an impact for Upper Clutha when he came on, while hooker Scott Cunningham was into everything.
Arrowtown never took a back step in the first half, playing with power and purpose and taking all the chances which came along.
Midfield back Nic Egerton and flanker Lachie Chalmers played well for Arrowtown.
Maniototo also left it late to beat Alexandra 22-17.
Midfield back Daniel Adam scored late to break a 17-all deadlock.
Young fullback Doug Smith ran hard and scored two tries while Jack Wild also did well for Maniototo. It was an entertaining game and was even throughout, having been tied up 10-all at the break.
Alexandra on its home track was a strong starter and got on top of its opponent at times.
Nathan Craddock stood out at the back.
Wakatipu had a good 43-8 victory over Matakanui Combined in Queenstown. The combined side got out of the blocks well and was ahead 8-0. It was hitting rucks and winning the set piece. But Wakatipu finally got its game together and was well ahead at halftime.
Wakatipu No 8 Brad Cross had a fine match, while Mike Rewi and Jamie Natapu grabbed two tries each.
As expected the Cromwell Goats won big over the Cromwell Cavaliers, with a 76-5 scoreline.
