The Sky Blues stormed fortress Windsor - or the National Stadium if you prefer - and grabbed the County Antrim Shield for the second time in four seasons.
In November, 2012 United stunned Linfield after winning a penalty shootout at The Oval so they had form when it comes to wrecking parties and it was the Blues who were hurting again last night.
After losing an Irish Cup Final to Glenavon and League Cup decider to Cliftonville the Sky Blues faithful feared another painful hard luck story but this time they had the last laugh.
Linfield were favourites to win this final but there aren't many predictable things in life - apart from rain clouds over Northern Ireland - and Irish League football consistently throws up surprises.
Paddy McNally headed the Sky Blues in front on 32 minutes but Guy Bates cancelled that advantage seven minutes into the second half.
It was Ferguson's troops, however, who produced a cutting edge in the second half with David Cushley (59) and Eoin Kane (76) finding the net.
Mark Stafford's header in the 85th minute sparked a tense final few minutes and Linfield struck the woodwork twice in injury time but United held on.
Guy Bates was promoted to Linfield's starting line-up for the suspended Paul Smyth while McNally filled the boots of the banned Johnny Taylor, both players paying a heavy price for dismissals in the Irish Cup battle.
United played three at the back and looked to push men forward but even though they were competitive in the opening half they were fortunate to be in front at the interval.
Ferguson's men took their one clear chance in clinical fashion while the Blues had several opportunities to strike first blood.
In the seventh minute Bates's drive bounced off the chest of Jim Ervin and away to safety and on 16 minutes Jamie Mulgrew's piledriver shook the crossbar.
The Sky Blues made sporadic bursts forward but were restricted to long range efforts from Cushley.
The United dangerman was fortunate not to be booked for a challenge on Mulgrew but seconds after he did foul the winger in the 32nd minute Tony Kane's free-kick gave McNally the chance to find the net with a superb downward header, the defender climbing above Mark Haughey to inflict maximum damage.
Linfield were missing Smyth's energy and drive but United's defence was defiant when put under pressure.
In a lively start to the second half Waterworth blasted a shot over the bar while GARY Thompson's effort drifted wide of the post.
The first booking came in the 51st minute when Allan Jenkins was guilty of dissent after protesting at the awarding of a free-kick. A minute later United conceded the equaliser when Niall Quinn's free-kick was flicked up into the air by keeper Alan Blayney and when the ball dropped Bates hammered it home from close range.
The Braidmen were on the canvas but they bounced straight back up again as Cushley's low, powerful drive in the 59th minute deflected off Stafford and flew past keeper Ross Glendinning.
The injured Matthew Clarke was replaced by Ross Gaynor and Aaron Burns came on for Niall Quinn as the Blues tried to hit back and Sean Ward's drive sailed past the upright.
Blayney tipped over Jimmy Callacher's quickly taken set piece and just when it looked the Blues might level the contest United scored a third.
Eoin Kane was allowed to burst past Stafford in the penalty area and drill a shot into the roof of the net.
Linfield fought to the end and Stafford's header from Jonny Frazer's cross with five minutes remaining set up a nervous finale.
In the fourth minute of stoppage time Kirk Millar's shot hammered against the crossbar and in the fifth minute of added time Stafford struck the post.
A brave effort from Linfield but this was the Sky Blues' night.
The Ballymena United players are heroes - for more than one day.
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