A converted try by flanker Sean Stapleton four minutes from end of a disappointing contest stretched Canterbury’s winning streak to three games.
They had to scrap for this one but if the quality of the rugby was never much to shout about you could never question their character and commitment.
Guernsey made life awkward, particularly in the first half when the islanders had an edge at the set scrums, slowed down possession expertly and forced the city side into uncharacteristic errors.
It was only after the break that Canterbury managed to lift the tempo and take the lead but still their mistakes were punished.
Two penalty goals from Henry Greenhalgh put the islanders five points ahead going into the final ten minutes.
Retrieving the situation required something special and it was the city club’s hard working pack who came up with the answer.
It started with the immaculate lineout jumping of Matt Corker and company as they set up a driving maul 22 metres out.
Brilliantly controlled, it rolled on unstoppably to end under the Guernsey posts. Official statistics credited Tom Best with the score after he added his heft to the final surge. However, it was one of those deserving forwards, Sean Stapleton, who really made the touch down and Ollie Best kicked the winning points.
Canterbury’s joy was understandable after defences ruled for much of the day and neither side found the accuracy to turn promising positions into points.
The first half was heading for stalemate until the 39th minute when Guernsey built pressure from a catch and drive and flanker Robin le Cocq crashed over for a short range try which Greenhalgh converted.
Things looked up for Canterbury after the break as they at last generated some quick ball and began to dominate territory.
Ollie Best got them on the board with a penalty goal and a blind side attack saw Corker’s pass give JJ Murray enough space to stretch over for the try and grab the lead.
If that put a fresh spring in their step it was undermined as errors crept in again and Guernsey took full advantage of the penalty count via Geenhalgh’s boot.
Then came that final flourish and the city club flew home reassured by the knowledge that they can succeed while operating well below par.
Canterbury: A.Moss, C.Grimes, T.Best, S.Sterling (repl F.Morgan), J.J.Murrray, O.Best, K.Braithwaite (repl D..Smart), J.Green (repl A.Cooper), J.Otto, S.Kenny, R.Cadman, M.Corker, L.Whetton (repl J.Stephens), S.Stapleton, S.Roche