Carlisle knew they had to go all-out for three points and rely on results elsewhere if they were to keep their play-off hopes alive, and they were up against a Crawley side who had already secured their League Two status.
Hamstring injuries to Jamie Devitt, Kelvin Etuhu and Danny Grainger ruled them out, so that meant a return to the 4-3-3 starting line up for midfielder Regan Slater.
Storm Hannah hit Brunton Park just before kick off, with sizeable hail stones battering into the players as they walked out of the tunnel.
There were huge appeals for handball as O'Hare tried to find Scougall with just two minutes on the clock, but the referee appeared to be unsighted as he waved play on. Carlisle stayed forward and Miller sent a shot from distance wide as it opened up for him.
It was a good start from the hosts but Slater was caught in two minds as he reached the edge of the box following an excellent move. His hesitation, just as he shaped to shoot, allowed McGuire to step across and make the block.
Wide man Nathan Thomas was twice blocked as he cut inside to make room, with the bulk of the early play taking place at the Waterworks End.
Slater arrived late once again as the Blues surged forward, and he spotted Thomas in acres of space as he went on the overlap. A neat touch was followed by a drop of the shoulder and an unstoppable thunderbolt as he sent a rasper past the dive from Morris to open the scoring on the day.
It became a one-man show as, just two minutes later, Thomas wound his way in from the right flank once more. He kept the ball for what felt like an age as he mesmerised the back line with his movement, and Morris was left to pick the ball out of the net when a low, driven shot nestled in his bottom corner.
Confidence was high and Hope was a whisker away from converting a fizzed cross from Scougall which teased its way across the six-yard box. And the Cumbrians were left feeling hard done by on the quarter hour as O'Hare went clean through with just Morris to beat. A tug on the shirt from Nathaniel-George left United's attacker on the floor, but the officials missed the moment and the penalty appeals were ignored.
It was turning into a rout as O'Hare dusted himself off to react first to a parried shot from Slater. Hope and Thomas were heavily involved in the build up as the home side queued up to put it away, but it was the Villa loanee's volley via the underside of the bar which did the trick.
The celebrations were followed by a switch, with Jason Kennedy coming into the fray as O'Hare signalled to the bench that the challenge for the earlier penalty incident had taken its toll.
Thomas was after his hat-trick and a curling shot was target bound until it flicked off Kennedy and spun away to safety. But the lead was extended to four goals just past the half hour when Hallam Hope looked up and saw a huge gap when the ball came his way 26-yards out. He wound his foot up and slotted it away with an inch perfect strike.
Collin was needed to tip an effort from a tight angle from Palmer over his bar, as Crawley mounted a rare attack, and there was more danger at the other end as Hope ran past his marker to deliver low. Kennedy was waiting to tap it in but Morris threw a boot out to hack it behind.
The Red Devils nicked one back on the stroke of half time when Nathaniel-George played a one-two with Palmer inside the area. That left him with just Collin to beat, and the stopper had no chance as a toe poke rolled under his body.
A tame effort from Camara signalled the start of the second period with Collin on the spot to snap it up. The stadium held its collective breath when Thomas went in search of his third goal when he took the pass on his toe with just McNerny to get past. The defender did just enough to prevent the shot.
The referee inadvertently helped United to mount an attack as a clearance from Young came off his shin. Hope ran away with it and his pass found Kennedy with his back to goal. Defensive errors allowed the popular midfielder to cut the ball back, but McGuire hooked it away.
Collin had to save a header from McNerny on his goal line as Crawley made more of a fight of it, and he was needed again when Grego-Cox beat the offside trap. The keeper covered his angles and spread himself to beat the drive away.
A clear-cut opportunity to pull another goal back was spurned by Morais when he was first to a parry from a save from a fierce Gambin effort. 10-yards out he had the width of the goal to aim at, but he leaned back and clipped it over the bar.
Crawley lifted the spirits of their 76-strong travelling band of faithful supporters when a dipping cross from Young was met on the full by defender Anthony Gerrard. He could do nothing as it came off his boot and headed over the line, despite the best efforts of Collin to claw it away.
A fine save from Morris denied Hope a celebration as he tried to bend it into the bottom corner as Carlisle broke, but an even better save from Collin stopped Grego-Cox in his tracks as he came through unhindered. A firm touch from the big keeper was enough to take it past the upright.
United saw the game out and claimed their points, and it now all comes down to the final weekend as the Blues make their way to already relegated Yeovil knowing that only a victory will keep them in with a shout.
Carlisle United - Thomas (7, 9), O'Hare (20), Hope (31)
Crawley Town - Nathaniel-George (44), Gerrard (og 77)
Crawley Town - McNerny (20), Dallison (90)
Carlisle United - Collin, Liddle, Gerrard, Parkes, Miller, Scougall (Gillesphey 81), Jones, Slater, Thomas, O'Hare (Kennedy 24 (Cullen 69)), Hope. Subs - Gray, Glendon, Simpson, Branthwaite.
Crawley Town - Morris, Young, McNerny, Grego-Cox, Palmer (Gambin 58), Nathaniel-George, McGuire, Dallison, Bulman, Morais (Willock 71), Camara. Subs - Mersin, Doherty, Sesay, N'Gala.
Referee - Mr Scott Oldham
Attendance - 4,514 (76 away fans)