Darren Boyce's early strike gave Ballymena a third derby victory over the Bannsiders this season.
Boyce netted against his former club after just two minutes with a header from Neal Gawley's corner.
Ian Parkhill and Jamie McGonigle went close as Coleraine pressed for an equaliser while Gary Thompson fired over for the visitors.
It was a poor second half with Coleraine keeper Andy Findlay denying Matthew Shevlin five minutes from time.
It was the perfect start for the Sky Blues as Boyce rose highest to net from Gawley's pinpoint delivery.
The lead was maintained thanks to Coleraine's poor finishing, with Parkhill going close before McGonigle went clear, only for Tim Allen to save at his feet.
John Watt saw his 20-yard strike flash wide and Thompson threatened for United before Parkhill found the net, only for his effort to be ruled out for offside.
It was a lacklustre second 45 minutes at the Showgrounds although both sides squandered good openings.
Coleraine substitute Gary Browne volleyed over on the stretch from a Brad Lyons cross while Findlay tipped Gawley's shot round the post.
Matthew Tipton put teenage substitute Shevlin through on goal late in the game but Findlay made a great save with his legs.
The victory takes Glenn Ferguson's side to within one point of the Bannsiders in seventh.