Carlisle have only scored seven away goals in ten League One matches and, on this showing, it was easy to see why. The decisive goal arrived in the 63rd minute when a curling free-kick from Danny Jackman was met by the head of Crowe, the ball rocketing beyond Tim Krul in the visitors goal. It capped a man-of-the-match performance from Crowe who also scored when the two sides met at Sixfields in a 2-2 draw last December.
There were few chances in a tepid first half but Northampton had the only one of note when Scott McGleish brought down a cross from Liam Davis and fed Jackman who jinked inside before crashing a shot which Krul saved with his body. Even then the danger wasn't over but Michael Liddle hacked the ball off the goal-line.
Carlisle missed a glorious chance to nose in front ten minutes after the restart when Richard Keogh scooped a ball over the bar from just three yards out after Graham Kavanagh's free-kick had landed in front of him. That was the signal for Crowe to put Northampton in front with his fifth goal of the season and the only question in the closing quarter was whether the hosts would cement their advantage.
They nearly did so in the 77th minute when Kyle Walker raced 50 yards upfield before delivering a cross which substitute Adebayo Akinfenwa slid wide. Northampton twice hit the woodwork in the closing minutes with Akinfenwa releasing Leon Constantine only for the striker to hit the post as he bore down on Krul's goal and then Andy Holt slammed a 20-yarder against the base of the same post in stoppage time.