For the third Saturday in a row, a former Cobblers player scored against his old side as Town were condemned to a fourth straight defeat, at Luton.
Luke Guttridge was the old boy on target at Kenilworth Road, where his 90th-minute goal was enough to sink his former employers and put his current club top of Sky Bet League Two.
It was an improved performance but one for which they still gained no league points - the timing of the decisive goal meant they had no margin in which to drag themselves back into the contest.
There were three changes to the Cobblers’ start, with Ben Tozer replacing Danny Alfei at right-back, Alex Nicholls in for Ivan Toney and Ricky Ravenhill swapping with Darren Carter, who did not travel due to a back injury.
The smell of sulphur from the pre-match smoke bombs still hung in the air when Luton’s midweek hat-trick hero Mark Cullen burst clear of the defence before being stopped in the penalty area by an inch-perfect Gregor Robertson tackle.
Northampton defended the corner well and enjoyed a good 10-minute spell in which they saw lots of the ball in advanced areas but did not carve out an clear chances.
Luton looked dangerous, though, always looking to play quick and early, and Andy Drury exemplified that when he cut inside before curling a shot narrowly high and wide of the target with his left foot.
John-Joe O’Toole glanced a Ben Tozer cross at goal for the game’s first shot on target but Mark Tyler made a comfortable low save and held the ball.
Luton made a bright start to the second half and forced a string of corners without Jordan Archer making a save.
Tyler did well to keep out a low Nicholls shot after he had been picked out by Enda Stevens after a puncturing run down the left wing.
Another spell of chanceless Luton pressure was then broken by a Nicholls-led counter which ended with a tame Joel Byrom shot before Luke Guttridge, who was applauded onto the pitch by the Northampton fans, had the hosts’ first shot on target with a low drive that was blocked by Archer.
Luton looked threatening without ever really dominating the game but got into a good scoring position five minutes from time when Robertson was somewhat harshly adjudged to have held back Paul Benson 25 yards from goal.
Drury struck it hard and low but it hit the heel of team-mate Luke Wilkinson in the box and rebounded to safety.
But Guttridge had the final say, collecting a loose ball after a Jim Stevenson cut in from the right wing and played a pass which deflected and dropped perfectly into the midfielder’s path.
Luton: Tyler; Harriman, McNulty, Wilkinson, Griffiths; Lawless, Smith, Doyle, Drury, Ruddock; Cullen
Subs: Benson (for Ruddock 44), Stevenson (for Doyle 46), Guttridge (for Lawless 61)
Not used: Lacey, Wall, Justham, Walker
Cobblers: Archer; Tozer, Cresswell, Robertson, Stevens; Mohamed, Byrom, Ravenhill, O’Toole, D’Ath; Nicholls
Subs: Toney (for Nicholls 63), Hackett (for O’Toole 76), Sinclair (for Ravenhill 90)
Not used: Duke, Alfei, Langmead, Moyo
Away fans: 1,018