The hosts went ahead in the 50th minute when Lee Mansell fired them ahead after good work from Wayne Carlisle.
But Stanley restored parity in the 69th minute when substitute Chris Turner's superb angled ball from the right enabled striker Michael Symes to convert from six yards.
The same combination were denied when home goalkeeper Scott Bevan made a superb 73rd-minute save to keep out Symes' downward header.
Carlisle's far-post header came back off the crossbar in the 76th minute following a superb deep cross Mustapha Carayol. But the Gulls were not to be denied and Kempson put through his own net under pressure from Ashley Barnes to ensure a miserable journey home.