The Cobblers’ winning streak came to a shuddering halt with a defeat at rock-bottom Hartlepool United by a single goal.
Pools prevailed thanks to Marvin Morgan’s 51st-minute strike, taken after a grave defensive error, to settle a game of few chances and one in which Northampton were some way below their best.
It means they slip to 13th in Sky Bet League Two and sees the gap to the play-off places grow to six points.
It was also the first time Town have failed to score in a game since the 2-0 loss at Southend United at the end of November.
John-Joe O’Toole registered the first effort on target of the game with a tame sidefooted effort which goalkeeper Scott Flinders held with some ease. It would set the tone for the powder-puff nature of the Cobblers attack.
After it, the next 25 minutes were controlled by Hartlepool, who consistently turned the visiting defence and forced them to knock the ball out of play for throw-ins in their own half.
Pools then played from there and for long periods they were unable to find the killer final pass, either rushing it or opting to play backwards or square.
Town increased their intensity around the half-hour mark and began to press the home team in their own half, a strategy which almost paid off when Ricky Holmes picked out Marc Richards, whose firm shot was well blocked by David Mirfin.
O’Toole almost mopped up with a flashing volley after Lee Collins’ stooping header had been blocked amid an almighty scramble at a corner but the teams went in all square and goalless at half-time.
Holmes got the Cobblers off the a bright start when he beat offside and drew a good blocking save from Flinders in the second minute of the second half but shortly afterwards the home side had the lead.
It was a fortuitous goal but completed a nightmare five minutes for Collins, whose attempted pass out of defence hit the heel of defensive partner Ryan Cresswell to give Morgan a clear run at goal.
From there, he confidently swept home his first goal since a January free transfer from Plymouth Argyle.
It was almost doubled immediately when Hartlepool defender Scott Harrison drove a volley wide of the target but deflected to the opposite side of the goal by a diving Cresswell block.
Jack Compton then drew a good save from Duke as Northampton made a double substitution and tactical switch, putting on Ivan Toney and Ben Tozer and changing to a 3-5-2 formation.
It didn’t really work. Toney looked more interested in conceding fouls than anything else and when he did get a glimpse of goal his volley was weak, into the ground and easily taken by Flinders.
The goalkeeper had a quiet evening, even in the final stages and with Northampton pressing hard for an equaliser.
He made a very good save in the final minute of added time to deny Cresswell a looping header and although that corner was bundled away for another, it was eventually dealt with by the home defence and their victory was secured.
Hartlepool: Flinders; Duckworth, Harrison, Mirfin, Austin; Franks, Woods, Tshibola, Compton; Morgan, Harewood
Subs: Jones (for Franks 78), Featherstone (for Morgan 78), Smith (for Compton 89)
Not used: Maxted, Holden, Walker, Richards
Cobblers: Duke, Moloney, Cresswell, Collins, Horwood, D’Ath, Taylor, Byrom, Holmes, O’Toole, Richards
Subs: Toney (for D’Ath 57), Tozer (for Holmes 57), Hackett (for O’Toole 74)
Not used: Carter, Bodin, Snedker, Newey
Cobblers fans: 132