BRIAN Gartland opened the scoring for Portadown after seven minutes when he met a Jamie Tomelty corner at the back post with a downward header past Wayne Drummond.
The visitors doubled their lead on 26 minutes after Matt Tipton knocked the ball back from the touchline for Kevin Braniff to fire into the roof of the net from 12 yards.
But United pulled one back on 29 minutes through an Alan Teggart left-foot drive from six yards after Tony Kane had crossed from the right.
Then, seven minutes before the break, they levelled thanks to former Portadown favourite Gary McCutcheon who converted from the spot after he had been brought down by Gartland, who received a straight red card from referee Raymond Hetherington for his trouble.
However, just over a minute into the second half, Sean Mackle restored Portadown's advantage with a powerful strike from the edge of the area after Braniff headed the ball down into his path.
Ballymena refused to let their heads drop, forcing a double save from David Miskelly before McCutcheon produced a stunning goalbound curling effort which the Ports 'keeper answered with an equally spectacular stop.
Roy Walker's side suffered a blow on 85 minutes when Denver Gage was dismissed for collecting his second booking before, sixty seconds later, the Ports set the seal on their victory with four minutes remaining when Neil McCafferty sent over a free-kick which Braniff met with a downward header at the back post.
Ballymena United: Drummond, Kane, Vauls, Gage, McCutcheon, Jenkins, Teggart, Surgenor, Baker, Downey, Watson subs Stewart (not used), Taggart (not used), Costello (not used), Woods (replaced Kane 64), Boyd (replaced Downey 64)
Portadown: Miskelly, Mackle, Redman, O'Hara, Ramsey, Tipton, Braniff, Mouncey, Tomelty, Gartland, McCafferty subs Breen (replaced O'Hara 82), Boyle (replaced Braniff 89), Clarke (not used), Murphy (not used), McCabe (replaced Tomelty 57)
- Curtis Woods and Tim Mouncey at The Showgrounds (Picture: Lorcan Doherty/PressEye.com)