It was a "must-win" game for City after three successive defeats, and two goals from the fit-again Kieffer Moore and one from man-of-the-match Andy Watkins were enough to give them a precious and entertaining victory.
With Moore striking just before and after half-time to put City 2-0 up, the home side looked on course for a relatively comfortable win against the Essex visitors. But they then lost goalkeeper Tim Sandercombe, who had just been beaten by Leon McKenzie's low drive, to a knee injury sustained in the first half.
Truro captain Jake Ash took over in goal, with City player-manager Lee Hodges coming on to take Ash's place at the heart of the home defence. The stand-in glovesman went on to make several crucial saves after Watkins had put City 3-1 up with a close-range header in the 66nd minute.
City's skipper was beaten deep into stoppage time, though, when McKenzie scored his second goal of the game, after the ball had run loose following a great save by Ash. However, the goal came too late as the Cornish side were able to celebrate a morale-boosting win.
In the first half Watkins missed a couple of early openings for City with Tambeson Eyong wasting the visitors' best chance when he shot wide. But, just when the half seemed set to end goalless, Watkins found Moore on the edge of the area and the young striker controlled the ball well before drilling the ball past goalkeeper Joe Wooley and into the far corner.
Moore's second goal was even better as he lashed the ball into the roof of the net from a pull-back by Watkins four minutes after the interval. But, with Sandercombe hardly able to move because of his injury, McKenzie took advantage of the 'keeper's immobility to race on to a through ball and finish well.
City needed a third goal and it came after 66 minutes, when Marcus Martin at the far post headed a free -kick from Hodges back across goal for Watkins to head home from point blank range.
Hornchurch were far from finished, however, and the City goal had several narrow escapes but, with some determined defending and Ash's heroics in goal, they stayed firm until McKenzie's late effort.
In the rain and wind, it was a delighted Truro team who celebrated three priceless points at the final whistle. Saturday's result means that City are ten points adrift of third-from-bottom Hornchurch, who occupy the highest of the division's three relegation positions, and have two games in hand on the Urchins.
