Colin Luckett's penalty-kick early in the game gave Cray their third win in a row, and moved them up to thirteenth in the Ryman Premier table.
Leigh Bremner set up the goal with a surging 40-yard run into the penalty area, where he was sliced down by a chasing defender after 13 minutes.
From the penalty-spot, Luckett tucked the ball low past the 'keeper's left, and that was enough for a solid-looking Cray side to end Hornchurch's run of nine games without defeat.
All the best chances in the first half fell to the home side, with near misses from Rob Quinn, Tommy Tyne, Marcus Cassius and Mark Willy.
Using the offside trap to good effect, the Wands stayed out of trouble in the second half, and went close to increasing their lead from some late raids on the Urchins goal.
George Porter had a shot well saved, Cassius fired too high when presented with a good chance, and Willy saw his header blocked on the line.
Cray travel to Tonbridge Angels on Tuesday evening (7.45pm).
Cray; Brennan, Lover, Luckett, Quinn, Willy, Day, Standen (Porter 61), Tyne, Bremner, Cassius, J Wood (Carpenter 78). Subs not used: Aris, L Wood, Jenkins.
Cray Wanderers have announced their 150th anniversary celebrations in 2010 are to include a Grand Ball in aid of the 'Bromley Y' youth charity.
The event is at Oakwood House on 5th June, and tickets are now on sale via the club or from the charity organisers on 07850 615297.
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