In terrible conditions at Ferney Park, Ballymena grabbed victory to move above Ballinamallard into eighth in the table.
Glenn Ferguson's started the game brightly and should have easily been ahead through numerous chances. Allan Jenkins somehow missed from only a metre out whilst Cushley was also guilty of passing up an opportunity as Jim Ervin and Neal Gawley's crosses from the right posed real problems for the Mallard backline.
The Mallards should have scored themselves just before half time when goalkeeper Dwayne Nelson slipped on his way to a short backpass, but Steve Feeney couldn't capitalise and put the ball wide.
The home side also had a strong penalty appeal turned away before half time with the ball appearing to hit Kyle McVey's hand.
The Mallards improved after the half but struggled to test Nelson in the Ballymena goal.
The only goal of the game arrived on 70 minutes with Allan Jenkins converting from the penalty spot after Ross Dunlop adjudged Liam McMenamin to have fouled David Cushley.