Celtic were denied anything from a game they put a lot into by a deep into stoppage time winner from Tom Hamblin.
Celtic started like a house on fire, straight at the hosts, Mitchell Austin attempting to run the ball into the net, only to be brought down by Mike Green the City keeper. A braver referee would have sent Green off, but a booking was all that was awarded. Adam Pepper took the penalty giving Green no chance.
Austin attempted to repeat the trick, but Green took the ball cleanly this time, before an overlapping run from Kelvin Bleau wrong footed the City defence, and his whipped in cross was met by the head of Jack Laird to give Celtic a two goal cushion.
A sliced clearance from Tim Ryan was adjudged to have been a back pass by the Celtic assistant manager when Alex Cairns collected it. Just yards from goal, Darren Mullens blasted at the goal, and despitre the array of Celtic players on the line, the ball smashed into the back of the net.
Celtic's two goal cushion vanished just before half time when the perennial problem of marking on corners allowed Tom Hamblin to sneak in at the back unmarked and nod in the equaliser.
It took Celtic until midway through the second half to regain the lead, Mitchell Austin coming out on top in the one-on-one with Green to slide the ball past him after an inch perfect through ball from Pepper.
The lead lasted less than ten minutes, though it was a great goal from Stephen Davies, bringing down Will Morfords cross and curling it into the top corner from twenty-five yards.
Scenting the chance of a win, Gloucester threw everything forward, with Morford denied by a reaction block from Cairns, and Jordan Barrow getting a leg on MAtt Coupe's effort putting it out for a corner, deep into stoppage time. It was heartbreak for Celtic as Tom Hamblin once again arrived unmarked into the box at the exact spot the ball came into, and put his side into the lead to take all the points with barely seconds left on the clock.