Northampton won a seventh straight home game, with Ben Harding's goal enough to beat improving Bristol Rovers.
Harding netted with two minutes left, latching onto Ben Tozer's long throw.
Rovers dominated for long spells and came close through Joe Anyinsah and Oliver Norburn in the first period, both denied by Lee Nicholls.
The Cobblers keeper was also in fine form to deny Eliot Richards twice after the break, while Tom Parkes volleyed wide before Harding's late winner.
Aidy Boothroyd's side remain a point behind third-placed Burton, while Bristol Rovers are three points above the relegation zone.
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Bristol Rovers manager John Ward told BBC Radio Bristol:
"I believe we deserved a point and I think even biased people will look at that and think we're a bit unfortunate not to get something.
"The way the goal came about didn't surprise us as we were defending all evening and did it pretty well.
"The ball dropped nicely for them and not for us, but I just said to the boys, if you're going to get beat, that's the way you want to get beat, going right through to the end.
"They're more annoyed than disappointed because they've worked really hard to try and get something from the game."