Mick McDermott’s Glentoran produced a stunning second-half performance to claim three crucial points at the Oval.
Although the East Belfast side dominated, they found themselves a goal down at the break courtesy of a Cathair Friel spot-kick that just about crept over the line after Glens goalkeeper Marijan Antolovic had saved his initial effort.
But whatever McDermott said to his troops at half-time, it worked a treat.
They were level within six minutes of the restart with another Hrvoje Plum special before Robbie McDaid headed a second.
Skipper Marcus Kane managed to seal the deal – a result which hardened the Glens’ slot in the top half of the table.
Glentoran were led out by Oval great of the 1940s, Bertie Wright, to mark the occasion of his 100th birthday.
The club also made a pitch-side presentation – and the performance must have thrilled the former player.
Young Paul O’Neill had the first sniff of goal but, unlike Patrick McClean who scored a stunner against Larne last week, he completely fluffed an attempted scissor-kick after being picked out by Conor Pepper’s accurate pass.
McDaid was next to try his luck after scything through the United defence, only to see his low shot flash past the post.
The home fans had loud appeals for a penalty kick on 19 minutes when the jet-heeled Elvio Van Overbeek twisted and turned inside the box before seemingly being impeded by Andrew Burns. Referee Tim Marshall wasn’t interested.
In another lightning raid, Overbeek stung the hands of goalkeeper Ross Glendinning before O’Neill let fly from distance which failed to trouble the United shot stopper.
The visitors had to wait until 33 minutes for their first sniff of goal. Josh Kelly’s cross was met by Leroy Millar, but his header was easily dealt with by Antolovic.
But they really should have been in front two minutes before the break. In a devastating break on the right, Jude Winchster sent Kelly clear, he drilled in a low cross that was met by Friel but Antolovic produced an outstanding one-handed save at the near post.
United were not to be denied as they edged in front two minutes into injury-time - and in controversial circumstances.
Again, the damage was on the right with Andy McGrory drilling a low cross for Winchester, who attempted a little drag back but was hauled down by Pepper.
Friel stepped up only to have his spot-kick saved by Antolovic, but the striker followed up to just about touch home. Assistant referee Adam Jeffrey confirmed the ball had crossed the line.
Referee Marshall ran the gauntlet of abuse on the way off at the interval.
Glentoran were level just six minutes after the interval with a trademark Plum goal.
It was McDaid whose trickery on the left caught the United defence cold and, when he picked out the big Croatian, his thundering low drive ballooned the net before Glendinning could even move.
And the big home crowd were celebrating again on 58 minutes when substitute Navid Nasseri whipped in a cross from the left which came off the legs of United skipper Jim Ervin and spun on to the head of McDaid, who made no mistake.
Van Overbeek should have put the game to bed seconds later, capitalising on an error by Ervin, but after his initial shot was saved by Glendinning, the little Dutch start scoped the rebound over the top.
The Glens finished the job on 82 minutes. Plum’s corner-kick was met by the head of Kane as his header ripped into the roof of the net.
GLENTORAN: Antolovic, Kane, Peers, Gallagher, McDaid, McClean, Pepper, Crowe (Nasseri 51), O’Neill (Stewart 69), Plum, Overbeek (Frazer 87).
Subs (not used): Morris, Herron, Murray, Gordon.
BALLYMENA UNITED: Glendinning, Addis, Harpur, Friel, McCullough, Burns (Mayse 79), McGrory, Winchester (McGinty 65), Ervin, Millar, Kelly.
Subs (not used): Williamson, Kane, Carville, Balmer, Lavery.
REFEREE: Tim Marshall.