City then had a chance to extend the lead just after the hour mark when Elliott went over a Steve Woods challenge inside the box. However, United keeper Van Heusden saved Jamie Forrester's penalty.
There were more opportunities for City to seal the win, with Jon Walters shooting over from a crossfield pass, and Reuben Hazell putting the ball onto his own post.
Simon Clist then rattled the woodwork at the other end, hitting the crossbar.
Torquay continued to press for an equaliser, and Alan Fettis had to save from Martin Gritton, while David Graham shot just wide.
The equaliser came in stoppage time. Fettis blocked Graham's effort, but substitute Kevin Hill headed home the rebound to make it 1-1.