Terriers boss Peter Jackson ran to hug goalkeeper Paul Rachubka as the whistle blew on a crucial night for his side as they took a mighty leap towards promotion.
Bizarrely, Rachubka was a virtual bystander for 75 minutes without having a shot to save. But he made up for that during a frenzied finale with five critical stops, three of them out of the top drawer as Northampton suffered their first home defeat since before Christmas.
Match-winner Andy Booth, who scored a hat-trick at Sixfields a few years ago, scored the all important goal in the 53rd minute, touching home from close range after Jonathan Worthington's cross was nodded back from beyond the far post.
At that point Jackson's side looked like winning at a canter with teenage striker John McAliskey twice going close to adding to the lead, lobbing over the crossbar before seeing a 67th minute drive rebound to safety off the foot of a post.
But that was the signal for Rachubka to begin his super show. He firstly made a brilliant save from substitute Derek Asamoah, the tiny striker spinning sharply before cracking a terrific shot which was pushed away.
Ian Sampson then had a close-range effort cleared off the line before Martin Smith curled a free-kick just over the bar and Rachubka tipped away a crisp volley by Paul Trollope.
The Terriers goalkeeper needed a slice of luck for his piece-de-resistance two minutes from time when Marc Richards somehow found a way though the defensive wall with his free-kick from the edge of the box but as the home side almost began their celebrations, Rachubka saved the day with an outstretched boot.
While Northampton's play-off hopes had been dealt a blow, Huddersfield go to Hull City on Saturday for a mouthwatering clash of two sides looking certain to shortly celebrate promotion and Booth will be hoping to put the icing on the cake with his 100th goal for the Terriers.
Jackson said: "It will be a really tough game. Hull will be expecting it and we won't let them down.
"Let's hope Andy Booth can get his 100th goal and it could be the clincher."