A GOAL from the much-maligned Paul Hayes – his third of the season - set Brentford up for another three points in their pursuit of the play-off spots.
But it needed a penalty save from Simon Moore with 15 minutes to go to keep the Bees on track.
Hayes' 61st minute strike was no more than Uwe Rosler's men deserved after an aggressive start to the second half, in which Clayton Donaldson curled a left footer just over the bar and then headed a corner narrowly wide.
Carlisle, who had more or less held their own in a lacklustre first half, found themselves under the cosh the moment play resumed – the Bees boss having clearly inspired his troops to up the ante.
They bombarded the visitors and won corner after corner as they sought to gain the upper hand, and then establish a cushion.
Carlisle were not done though, and Mike Edwards went close to levelling it with a shot from the D that had Moore beaten, but went just wide, and they came even closer after 75 minutes when Tony Craig climbed all over United sub David Symington to concede a spot kick.
Joe Garner stepped up to make it 2-2, but Moore guessed correctly, diving to his left to block the shot.
Jonathan Douglas gave the Bees the lead on 20 minutes with a sweet volley at the far post from a Harry Forrester corner, but the advantage was short lived.
Just six minutes later, a fine run by Kallum Higginbotham down the right flank opened up the home defence and Garner controlled before drilling into the bottom corner.
Hayes' goal just past the hour put Brentford back in front, the striker lurking at the far post to get on the end of a flick from Toumani Diagouraga at another corner – this time delivered by Adam Forshaw.
Line-up: Moore; Logan, Dean, Craig, Bidwell; Douglas, Forshaw (Saunders 86), Diagouraga, Forrester (Barron 84); Hayes, Donaldson. Subs not used: Lee, Dallas, Oyeleke, German, Pierre.