With Blackpool having beaten Wolves with a late, late strike last Tuesday night United went to Morecambe knowing that only a victory in normal time would see them through to the knock-out stages of this season's Leasing.com Trophy competition.
The Blues were much changed from their Friday night exploits and the Shrimps had new manager Derek Adams in charge of his first game in the dug out.
Manager Steven Pressley opted for a 3-5-2 formation with defender Nathaniel Knight-Percival installed as team captain, and with Elliott and Iredale occupying the wide positions.
The game started at a fast pace with the ball moving from end-to-end and with both sides looking to get deliveries into the box.
Morecambe made the first chance of the night when Conlan overlapped on the left flank before whisking a good cross into the mix. O'Sullivan, who had started the move, chased after it but his touch on the stretch sent the ball wide.
Carlisle recovered their shape and a huge kick from Gray split the home defence. Loft was suddenly in a chase with Halstead as to who would get to it first and the keeper swung a boot to clear it in the nick of time.
There was a similar task for Gray to complete when Stockton and O'Sullivan combined to carve a way through for the Shrimps. The Carlisle stopper reacted quickly to race out and gather up the pieces.
United attacked again when Iredale bent his run from wide. Sagaf peeled away to ask for it, and a lovely reverse pass invited a cross. Lavelle had shadowed the run from Loft and the big centre back did enough to get in the way when Sagaf hooked it his way.
Carlisle broke well just past the quarter hour when Loft went on a surge from inside his own half. Sorensen was with him, and a rolled pass left the Newcastle loanee with a clean sight of the target. His shot was going into the top corner until Halstead went full length to tip it away.
It was the home side's turn to go close moments later when Stockton got on the end of another great delivery from Conlan. His header came off a defender and Gray watched in relief as it dropped past the post and into the advertising hoardings.
Back at the other end and Elliott lost his man tight by the corner flag before pulling it back for Carroll to strike. It had power but it was always too high.
Club history was made on 26 minutes when Jarrad Branthwaite picked the ball up and set off on a run. Covering over 40-yards he left Halstead with no chance when he let fly from the edge of the box. He became the club's youngest ever goal scorer, breaking a 29-year record, as the ball flew into the bottom corner.
Editor's Note - Branthwaite was 17 years and 138 days old when he bagged this goal - previous record holder Rob Edwards was 17 years and 250 days old (penalty v Maidstone, 8 September 1990).
United had defending to do when Alessandra was put into a dangerous position by Brewitt. His stinging shot was met by a wonderful two-handed save from Gray.
Carlisle looked lively and determined work from Bridge and Elliott on the right wing eventually led to a clipped pass from the midfielder. Sorensen had his back to goal but he met it with a scissor-kick which left Halstead rooted to the spot. The hosts were able to draw breath as it bounced up off the outside of the upright.
There was more work for the Blues to do just ahead of the break as Stockton and O'Sullivan led a probing period. Knight-Percival stopped one effort in its tracks and Gray was off his line to calm things down as he clutched the resulting corner.
But it was the visitors who went closest to adding to the goal tally in time added on for the half when Carroll popped a volleyed pass to Sagaf. He beat his man before forcing a diving parry from Halstead with an accurate 24-yard piledriver.
It was about possession for both teams after the break, with the Cumbrians looking the more effective as they worked it from left to right.
United had spells in the final third, as did Morecambe, but it was the hosts who were given a lifeline just past the hour when Elliott stuck a leg out as Wildig moved into the area. Referee Graham Salisbury pointed to the spot and Tutte rattled the spot kick into the roof of the net.
That gave Morecambe added momentum and they took the lead when substitute Leitch-Smith went on a break on the right flank. His cut back picked out Wildig, and he slid through Christie Elliott to get his toe to the ball and send it into the unguarded net.
Halstead had to punch an inswinging corner from Iredale over the bar as Carlisle looked for an equaliser, and Olomola had a goalbound rasper blocked as Iredale put a training ground corner routine his way.
Gray had to save as he went one-on-one with Stockton with the game suddenly alive and vibrant again, and the Shrimps striker blazed a poor effort high over the bar when he'd done the hard work of making space for the strike.
Substitute Harry McKirdy was a yard away from an equaliser on 80 minutes when he dropped a shoulder to beat his man. The crunching drive that followed stayed low but it angled past the woodwork.
United were disappointed when they worked a great position with five minutes left to play, when touches from Elliott and Bridge left Olomola unmarked. He tried to place his shot but he leaned back and it arrowed high.
Carroll was next to flash one wide when a half clearance came his way, and there was more frustration for the Blues as they peppered the box with deliveries and corners in the closing stages. The ball wouldn't quite fall and it was Morecambe who sealed the win in time added on when a block from a Wildig shot spun to Conlan. The left back caught it on the sweet spot and Gray had no chance, and the net buster brought an end to the involvement in the competition for the Cumbrians.
Morecambe - Tutte (61 pen), Wildig (67), Conlan (90)
Carlisle United - Branthwaite (26)
Morecambe - Halstead (gk), Conlan, Old, Tutte (Kenyon 75), O'Sullivan (Leitch-Smith 55), Alessandra (Sutton 55), Stockton, Brewitt, Wildig, Lavelle (c), Tanner. Subs - Roche (gk), Ellison, Miller, Cranston.
Carlisle United - Gray (gk), Branthwaite (captain from 69 onwards), Knight-Percival (c) (McKirdy 69), Mellish, Elliott (G Jones 84), Bridge, Carroll, Sagaf (Olomola 71), Iredale, Loft, Sorensen. Subs - Robinson (gk), Hayden, Charters, Walton.
Referee - Graham Salisbury
Assistant Referee 1 - Gary Hilton
Assistant Referee 2 - Joe Simpson
Fourth Official - Richard Aspinall
Attendance - 802 (169 away fans)