From a position of comfort Canterbury found themselves in a fight for survival before they came away with their fourth win of the National 2 East season to claim maximum points.
The biggest battle, however, was with their own poor discipline as a red card for flanker Harvey Furneaux in the second half left them a man short for 30 minutes, and their problems were compounded by three earlier sin binnings.
Havant, trailing by 24 points, exploited the situation with a hat trick of tries from hooker Sean Shepherd, the last coming in the 80th minute to earn his side a second bonus point.
There was little sign of the upheaval to come when Canterbury, after a tight opening quarter edged by the visitors, built a 24-12 half time lead and two tries in the first eight minutes after the break pointed to a routine victory.
They established that position of strength despite first half yellow cards for Dave Irvine and Garry Jones.
A Frank Reynolds penalty goal got the city side on the scoreboard after only two minutes but conceding penalties cost them tries by Havant forwards Steve Jenkinson and Sam Vince and a Joel Knight conversion.
Those scores sandwiched Canterbury’s opening try when they picked off an overthrown lineout, won a penalty and Eoin O’Donoghue plunged over from the maul.
Then Canterbury began to pull away as Aiden Moss finished off some precise handling in style and the impressive O’Donoghue peeled off a driving maul to register his second.
The early second half strikes, as O’Donoghue sent Moss across the line on the overlap and Sam Rogers timed his pass perfectly for Max Campbell to go clear for the fifth try, seemed to have settled matters, particularly with Reynolds missing only one shot at goal.
A yellow card for Henry Kenny was not welcome but in the 51st minute an isolated fracas broke out and Furneaux was singled out for punishment.
Havant saw their chance and a Canterbury side still too often on the wrong side of the referee gave them plenty of scope to mount a massive offensive through their pack.
Shepherd’s tries all came from powerful close quarter work and two conversions by Knight added to the pressure.
Canterbury hung on, just, but left themselves with big questions to address.
Canterbury: K.Heatherley, G.Jones, F.Morgan, W. Waddington, A.Moss, F. Reynolds, T. Williams, A.Cooper, E.O’Donoghue, D.Herriott, D.Irvine, J.Stephens, S.Rogers, H.Furneaux, C.Thomas.
Replacements: H.Kenny, O.Frostick, P.Farrance, M.Campbell, N.Morris.
Pictures supplied by Phillipa Hilton.