William Robinson smashed home Instonians winner four minutes from time to send their Kirk Cup Pool into the melting pot.
Inst were two up after only 12 minutes thanks to two goals from John Watson.
And it looked like Banbridge’s fourth choice keeper Peter Bingham was going to be in for a busy day.
But Inst failed to make their pressure tell and when Bingham denied Watson scoring his hat-trick five minutes into the second half, the pendulum was beginning to swing in Bann’s favour.
In a devastating 60-second spell, Bann were back in the game, when on 45 minutes Bruce McCandless smashed the ball past Inst’s new keeper Richard Johnston.
And Johnston hardly had time to take a breath when he parried a shot from McCandless into the path of Philip Brown who made no mistake from close in to level it one minute later.
However, it was Inst who had the final say, when they won their first penalty corner with four minutes remaining.
Up stepped Robinson, Inst’s top goal scorer last season, to open his account with an unstoppable shot to give Inst a deserved win.
“We worked very hard to get ahead early and to be fair, when we were 2-0 up we had a couple of opportunities to go further ahead,” explained Inst coach Mark Irwin.
“We then stepped off the pace and we let them back into it. But I was really pleased with the guys, how they got their composure back and our shape back and towards the end of the game, we were very dangerous on the counter attacks and on the balance of chances, I do think we deserved to win.
“It is important to make this place really difficult for teams to come to and we will know where we are at the end of this Kirk Cup campaign, as we have a tough test against Lisnagarvey next week.”
Meanwhile, holders Garvey, took a step closer to the semi-finals when they put Civil Service to the sword, knocking six goals past the visitors including two goals from Stuart McNeice.
Belfast Harlequins got an early season drubbing as Cookstown hit double figures to win 10-0 at Coolnafrankey, with Greg Allen and Gareth Cuddy scoring two a-piece.
Annadale notched up their second Kirk Cup victory when they won 4-2 at Kilkeel. Dale’s young guns were too strong for the home side, with Edgar brothers William and John grabbing a goal each.
In the Linden Cup, Bangor have put themselves in a commanding position in Pool B, as they won 3-2 at Newry, thanks to a goal from James Mottashaw three minutes from full time.
Meanwhile, Portadown went on a goal scoring rampage hitting eight past visitors South Antrim. And there were wins for North Down and Queens, over Raphoe and Armagh respectively.
In the Sussex Regiment Cup, John Young hit a hat-trick for Parkview, as they saw off the PSNI 4-1.
There were also wins for Ballymena and Cliftonville.