Carlisle United 0 Exeter City 1: An 89th-minute goal from sub Padraig Amond consigned Carlisle United to a late defeat at the hands of high-flying Exeter.
After holding off their second-placed visitors for most of the game, Paul Simpson's Blues were finally undone from a corner.
Amond's clinical finish meant the Cumbrians suffered a third defeat in ten games under Simmo and reduced their survival cushion to ten points as they dropped a place to 19th.
It came late in a contest where Matt Taylor's Grecians had been the dominant side without being able to put Carlisle to the sword.
United, meanwhile, struggled to create chances in a largely defensive display against opponents who look well set for promotion.
Kelvin Mellor came close to a goal in the second half but Carlisle were often on the back foot and had keeper Mark Howard and their centre-backs to thank for keeping them in the game until Amond's late winner.
The result, in front of a 5,132 crowd, means United cannot be totally sure of safety yet, with five games to go and second-bottom Stevenage's win at Colchester keeping them in the battle.
Defeats for other strugglers, including Oldham and Barrow, though, mean Carlisle still have a strong chance of completing the job, with the possibility they could seal their League Two status over Easter weekend.
United boss Simpson stuck with the same XI that started last weekend's 2-2 draw at Tranmere Rovers, also selecting the same subs.
It meant Danny Devine, Rod McDonald and Mellor continued in the side, while Morgan Feeney again captained the Cumbrians and Jon Mellish starting in midfield.
Exeter made one change, with captain Matt Jay back to replace Callum Rowe, while ex-United frontman Offrande Zanzala, on loan from Barrow, also started for the Grecians.
The opening stages were totally dominated by the visitors, who should have scored inside three minutes.
Jordan Gibson gave the ball away, allowing Jevani Brown to attack the box, but Morgan Feeney made a superb sliding interception to prevent Zanzala opening the scoring.
Taylor's men remained on top, regularly attacking the Carlisle box, Tim Dieng going close and Pierce Sweeney rifling wide inside the first six minutes.
Further pressure saw Dieng fire narrowly wide before Archie Collins sent a free-kick into the side-netting.
Carlisle were struggling to keep the Grecians at bay with their own attacking efforts coming to nothing in the opening stages.
Brown's poor touch prevented Exeter from opening United up again on 27 minutes, Collins' eventual shot blocked by Brennan Dickenson.
It took Carlisle 32 minutes to fashion any sort of chance - a low Omari Patrick attempt saved by keeper Cameron Dawson after a Dickenson long throw was worked back into the box.
A further burst of Exeter attacking then saw Jay test Howard from 25 yards after a good passing move, and from the resulting corner, Dieng's header drew a flying stop from Carlisle's keeper.
Zanzala then failed to get a header on target from a Josh Key cross shortly before half-time.
Simpson responded to Exeter's dominance by making a half-time change, Tobi Sho-Silva replacing Kristian Dennis, with Mellish firing an early second-half effort over the bar.
United, though, were then grateful to Howard again for keeping things level, the goalkeeper showing excellent reflexes to keep out Dieng's shot after the visitors had opened up Carlisle on the right.
Feeney then denied Dieng with a block, before Exeter boss Taylor replaced Zanzala with Amond just before the hour mark, the sub dipping a header just over the bar with one of his earliest touches.
Sam Stubbs then met an inswinging corner but headed over the bar as the wait for the opening goal went on.
Simpson replaced Dickenson with Mitch Roberts, before a corner fell to the young sub and he fed Mellor, whose eventual shot was tipped over by keeper Dawson.
That, though, was as close as United got.
Taylor made a double change for the closing stages and one of the subs, Josh Coley, went clean through with ten minutes to go, but lost his balance under pressure and the chance went with it.
Simpson then introduced Gime Toure for Patrick - but it was Exeter who finally struck in the 89th minute.
It came after Brown had won a corner on the left, and when the deep delivery picked out Dieng, his header was met by sub Amond in space and the striker headed clinically home.
That saw big celebrations in the away section among 403 travelling fans.
And Carlisle couldn't find a way back over five added minutes as Exeter wrapped up the win that keeps them five points above the play-off places.
United: Howard, Mellor, Simeu, Feeney, McDonald, Dickenson (Roberts 70), Devine, Mellish, Gibson, Patrick (Toure 81), Dennis (Sho-Silva 46). Not used: Norman, Riley, Whelan, Omotoye.
Booked: Gibson, Mellish, Dickenson, Simeu.
Exeter: Dawson, Sweeney, Sparkes (Caprice 78), Stubbs, Hartridge, Key, Collins, Brown, Dieng, Jay (Coley 78), Zanzala (Amond 58). Not used: Brown, Phillips, Rowe, Diabate.
Goal: Amond 89.
Ref: Tom Nield.
Crowd: 5,132 (403 Exeter fans).
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