Bury boss Graham Barrow was understandably delighted with his side as the Shakers registered their first win in 11 matches.
Goals from Jon Newby, his second goal in 22 months, and a second in as many games from Leeds' loan hitman Andy Keogh was enough for the Gigg Lane outfit to avenge two December defeats to Colin Calderwood's team.
And to add insult to injury, the visitors were reduced to 10 men on the hour mark when striker Trevor Benjamin, on loan from Leicester City, was sent off for elbowing Bury defender Colin Woodthorpe.
Having lost twice to The Cobblers already this term, Barrow's team were determined not to make it a triple of defeats.
And so it proved as the home side recorded their first win since November 27 when they beat Swansea City 2-1 at Vetch Field.
Newby hit the target with a rasping drive in the 42nd minute after a slip from Northampton defender Chris Wilmott, while Keogh took advantage of another mistake from Wilmott to score in the 58th minute to secure all three points.