A Gary McCutcheon hat-trick helped Ballymena come from behind to extend their excellent run of away form.
David Howland got the final touch to put the Glens ahead after 35 minutes.
McCutcheon levelled with a 52nd-minute strike, then headed in to nudge the Sky Blues ahead, before Andy Waterworth fired into the bottom corner on 77.
McCutcheon provided the cross for Allan Jenkins to head in at the back post on 82 and the former Ports striker completed his hat-trick soon after.
There was controversy early in the game when Jim O'Hanlon appeared to be upended by Aaron Stewart in the penalty area but referee Mark Courtney waved away penalty appeals.
Elliott Morris then made a fine save from James Costello's left-foot shot.
At the other end, Wayne Drummond palmed Sean Ward's 35-yard first-time shot onto the bar.
Howland broke the deadlock when he poked the ball home on the goal-line after Jimmy Callacher headed down Stephen Carson's corner.
Morris distinguished himself with another fine save from Jenkins before the interval, and again denied the Scottish midfielder after the break.
Drummond pushed Carson's shot round the post.
McCutcheon grabbed his first when the ball fell to him after the home side failed to clear.
McCutcheon netted again on 72 but substitute Waterworth restored parity when he cut clear of his marker and fired into the bottom corner.
Jenkins's strike and McCutcheon's third, his 12th of the season, ensured that Ballymena retained their 100% away record in the Premiership.