In a match which the visiting Urchins certainly had plenty of the ball, the home side took the lead through Joe Christou after 27 minutes in front of a crowd of 206.
Leon McKenzie equalised with 11 minutes remaining but Thurrock won the match in the final minute of normal time when Lewis Spence fired the ball home from the edge of the area.
Tuesday`s other game saw Harlow Town move to within five points of the top five with games in hand still on most above them after edging out second-bottom Haringey Borough by the odd goal in five.
Ryman League
Alex Read gave the Hawks a 12th minute lead that Dan Aristidou levelled 14 minutes later. Junior Dadson restored the visitors` lead on the half-hour mark, only for a David Hughes own goal to level matters once more after 68 minutes. But Mario Noto popped up with Harlow`s winner with 16 minutes to go.
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