Sam Hoskins scored twice in the second-half to add to Jon Guthrie’s long-range strike just before half-time, as Town made it three wins on the spin.
It was far from a vintage performance from Jon Brady’s men, but they did enough to emerge as deserved winners.
Here are Jeremy Casey’s player ratings from Sixfields….
1. Lee Burge
You wait eight matches for a clean sheet, and then two come along at once. In truth, Burge didn't have a serious save to make until the final seconds. Kicking was really poor throughout ... 7 Photo: Pete Norton
2. Sam Sherring
An unfussy player, Sherring showed his versatility by switching from right-back to central defence after Tyler Magloire's injury. A very solid defender... 7 Photo: Pete Norton
3. Tyler Magloire
Was mighty impressive before he was forced off with a hamstring injury after just 40 minutes. Fingers crossed his scan on Monday brings good news, because Magloire has been getting better and better ... 7 Photo: Pete Norton
4. Jon Guthrie
It has been a great week for the Cobblers skipper. Two near flawless defensive displays, and two goals - with the one against Rochdale an absolute gem. He might need to swing that left peg a bit more often! ... 8 Photo: Pete Norton