A brace from Matty Taylor was the difference between the sides on a horrible afternoon in the West Country as the Pirates grabbed only their second home league victory of the campaign.
The heavy conditions caused early edginess in the Carlisle ranks and a low cross from Montana had the back line stretched. Ellis watched it and went for safety first as he guided it behind.
A wicked corner delivery had Rovers interested and Gillespie was immaculate as he dived low to stop a thundering drive from Taylor. The loose ball was clipped back into the mix and the United stopper was at his best again as he somehow got across to palm a stinger from Sinclair away from the bottom corner.
The wind played a part as Taylor swung a high ball at the back post with Gillespie unsure as to the flight of the ball. He spilled it and he was relieved to see Atkinson step across to make a vital block.
Carlisle broke from their own half on the quarter hour and a touch from McChrystal from a Brough cross was just enough to take it safely past the far post.
It was better from the visitors and another whipped cross brought a challenge from McQueen inside the six yard box. Miller was in attendance but a whistle for a push on the keeper brought the move to an end.
Forward Derek Asamoah had two tame shots from distance in quick succession but he was almost sent clean through on half hour when Miller picked out McQueen on the right flank. His touch took him past his man and a neat flick towards the penalty spot was hooked clear by McChrystal just before the nippy striker could make his mark.
The game lost its momentum in the lead up to half time and the frustration at the lack of headway made by both teams was summed up when Montana found himself with the ball at his feet and 35-yards from goal. He had options left and right but he chose to shoot and he sent it high over the bar.
A James Clarke free kick from deep opened the second half but it was difficult for Parkes as he arrived late. He tried to lob his header over Gillespie but it dropped well wide of the target.
The impressive Mark Ellis blocked from Easter as Rovers tried to rediscover their early vigour, but the Pirates should have taken the lead on 55 minutes when Taylor lost his man for a Lines delivery. He climbed well but it spooned off the top off his head and high into the air. Easter followed it with another powerful attempt which was easy for the well positioned Mark Gillespie.
Carlisle thought they'd grabbed the lead just past the hour when Atkinson drilled a 40-yard free kick past the wall and into the box. Mark Ellis got a touch but he was disappointed to see it bend past the post with Nicholls well beaten.
The miss proved costly as McChrystal pounced on a loose ball deep inside his own half. With the visiting side committed to the attack a lightning quick break left them with just three defenders to face a line of five determined forwards. Bodin intelligently fed Lines and his low cross-shot was tucked into the waiting net by Matty Taylor.
A near post Sweeney header from a Brough corner went close, but there were chances at the other end as Easter slid in to volley right at Brough, quickly followed by a block from Taylor as he tried to find a way through.
The points were sealed with just three minutes left to play when a poor pass from Dicker set the hosts on the attack. It eventually came to Matty Taylor and he emphatically crunched it past Gillespie and into the back of the net from the edge of the box.
Bristol Rovers - Taylor (66, 87)
Bristol Rovers - Sinclair (9), Brown (52), McChrystal (55), Parkes (90)
Bristol Rovers - Nicholls, J Clarke, Parkes, McChrystal, Brown, Bodin, Sinclair, Lines (O Clarke 90), Montano (Gosling 83), Taylor, Easter (Blissett 87). Subs - Mildenhall, Kilgour, Mansell, Lucas.
Carlisle United - Gillespie, Miller, Atkinson, Ellis, Brough, McQueen (Wyke 78), Sweeney, Dicker, Balanta (Rigg 61), Thompson (Ibehre 61), Asamoah. Subs - Hanford, Hery, Osei, Archibald-Henville.
Referee - Mr Mark Brown
Attendance - 6,423 (353 away fans)