Cobblers' dreadful season took another turn for the worse on Saturday afternoon when they dropped to 21st in Sky Bet League Two with a desperate 4-0 defeat at Mansfield Town.
Mansfield's four goals, all of which were the result of poor defending, do not even account for several excellent saves made by goalkeeper David Cornell as Town were comprehensively outplayed and out-fought by their hosts on a truly abject afternoon at the One Call Stadium.
It is barely even worth repeating what undid the Cobblers here because it has happened so many times in recent months, but once again hapless defending, little creativity and an alarming inability to respond to an early setback allowed the Stags to sweep to their biggest win of the season.
Timi Elsnik's well-taken but poorly-defended opening goal on just five minutes set them on their way to victory before a rampant second-half performance left Cobblers to consider a very bleak future as Danny Rose scored twice and CJ Hamilton also netted.
Mansfield were hardly in sparkling form themselves ahead of this game and yet the Cobblers were helpless to prevent them creating chance after chance as the midfield went missing and defenders regularly lost their men, leaving Cornell to single-handedly keep them in the game prior to the second-half onslaught.
It previously seemed inconceivable that the Cobblers could sink any lower than their previous depths but they somehow managed it in Nottinghamshire where their inept performance will only ramp up the pressure on manager Dean Austin ahead of Tuesday's visit of Bury.
Matt Crooks and Shaun McWilliams picked up knocks in training and therefore missed out on the trip north as Austin made one change with Billy Waters starting in place of Crooks on the right-wing.
The other notable team news saw teenage midfielder Scott Pollock become the first player from the club's education programme to feature in the matchday squad after the 17-year-old took his place on the bench.
Town's hopes of keeping a second consecutive clean sheet lasted just five minutes when Mansfield's first attack culminated in an all-too-soft opening goal.
It stemmed from a Northampton corner as the home side cleared and the ball fell to Elsnik, who ran from one box to the other without any defender going near him before he cut inside and fizzed in a low shot that hit the far post and nestled into the net.
The precision of Elsnik's finish didn't excuse the dreadful defending that led to it and Town's back four continued to look vulnerable whenever Mansfield got into the final third with CJ Hamilton threatening a second.
Cobblers were mostly kept in check as an attacking force but a couple of chances came their way midway through the first-half when Sam Hoskins' cross cannoned off Sam Foley and fell kindly for goalkeeper Bobby Olejnik before Kevin van Veen's snap shot lacked power.
A disjointed opening period ended with a flurry of activity as both goalkeepers were called into action. Olejnik was the first to make a save, blocking with his legs after van Veen had glided past two defenders and taken aim from an acute angle.
The game then swung back up the other end where David Cornell kept Cobblers in the game ahead of half-time, tipping over Elsnik's venomous from the edge of the box before showing terrific reactions to keep out Matt Preston's close-range header in first-half stoppage-time.
Andy Williams replaced van Veen at the break but still Mansfield had the better of the play with Otis Khan clipping the top of the net with a 20-yard attempt within 90 seconds of the restart.
There was not much respite for Cornell either as he flinged himself to tip over Khan's free-kick and followed that by racing out to block at the feet of Tyler Walker, who then side-footed wide of the far post.
By this point three Northampton players - Leon Barnett, Ash Taylor and van Veen - had gone into the book and John-Joe O'Toole then joined them for dissent as the wheels threatened to come off.
And they did indeed come crashing off just shy of the hour-mark when Rose charged down Cornell's poor attempted clearance and the ball ricocheted nicely for the Stags striker to slide into the empty net.
Walker should have killed the game off once and for all but he took too long when getting behind Town's back four, although in truth a Northampton comeback always appeared highly unlikely.
Instead, Mansfield looked like adding to their lead as Cornell saved from Neal Bishop, and it was 3-0 soon enough as more weak tackling at the back allowed Hamilton to get free in the box and squeeze a shot in at the neat post eight minutes from time.
There was still time for more damage, Rose scoring his second when wrong-footing Cornell in the latter stages as the Cobblers slumped to a truly harrowing away defeat.
Mansfield: Olejnik, Benning, Preston, Pearce (c), Bishop, Khan (Davies 87), Sweeney, Walker (Atkinson 74), Elsnik (Butcher 90), Hamilton, Rose
Subs not used: Logan, Sterling-James, Gibbens, Graham
Cobblers: Cornell, Odoffin, Taylor (c), Barnett, Buchanan, Foley, O'Toole, Waters, Bowditch (Bridge 67), van Veen (Williams 45), Hoskins
Subs not used: Ward, Facey, Pierre, Turnbull, Pollock
Referee: Trevor Kettle
Cobblers fans: 485