Cobblers conceded two goals in the final 13 minutes to suffer an agonising 2-1 defeat at Bradford City on Saturday afternoon.
Charlie Goode's scrappy header was befitting a scrappy first-half at Valley Parade but Town didn't care at the break when they held a slender advantage.
The second-half was all one-way traffic, however, and Bradford's onslaught was belatedly rewarded with two late goals as the visitors were guilty of sitting too deep for too long.
Their defensive approach invited the pressure and Michael Harriman's own goal on debut was followed by Paudie O'Connor's late winner to leave Cobblers fans fearing last week's win over Plymouth was a one-off.
Cobblers' two new signings were both included in the matchday squad as Harriman made his debut at right-back, allowing Shaun McWilliams to move into midfield and replace the injured Ryan Watson, and Egli Kaja started on the bench.
The only other change to the side that beat Plymouth Argyle last weekend saw Joe Martin come in for Joe Bunney, who left for Bolton on deadline day.
Bradford started well at Valley Parade and they had the first opportunity when Goode's tackle ricocheted kindly to James Vaughan, but David Cornell stood up well to make the block.
An error-strewn first 20 minutes followed no real flow or pattern, with the game constantly disrupted by free-kicks and fouls, but, almost out of noting, Town broke the deadlock.
Just shy of the midway point of the first-half, Martin delivered an excellent inswinging corner from the right and Goode's header was eventually bundled over the line.
Matty Warburton's effort moments later was ruled out for offside before Clayton Donaldson's near-post flick dribbled wide of the far post as Bradford struggled to muster a meaningful response.
The hosts won a number of corners towards the end of the opening 45 minutes but they couldn't turn any of them into a goal and Town held sway at half-time.
Bradford came out with more gusty and impetus in their play after half-time and they were close to a leveller when O'Connor's header landed just wide of the far post.
Cobblers had to ride out the storm and they did well to take the sting out of Bradford's mounting pressure, though the home side still threatened, particularly from set-pieces.
Another excellent ball into Town's box only needed a touch and then Harriman's misjudged back header fell to Donaldson, but his header was scrambled off the line by Martin.
Cobblers had hardly done anything as an attacking force in the second-half but they very nearly doubled their lead with 16 minutes to go when a lovely clipped ball from Chris Lines landed on the head of substitute Vadaine Oliver, but former Town stopper Richard O'Donnell tipped over.
However, Bradford by far and away carried the greater attacking threat since half-time and they eventually made it count with 13 minutes to go when Zeli Ismail's fizzed cross was turned into his own net by the helpless Harriman.
Although City were then the more likely team to win it, O'Donnell denied Oliver for a second time when producing a smart stop at his near post.
It was all hands on deck at the other end, though, and unfortunately Town were unable to escape from Yorkshire with a point as City struck two minutes from the end. Cornell made a fine stop to keep out Kelvin Mellor's initial header but the loose ball fell straight to O'Connor and he gleefully tucked away the rebound.
The visitors had five added minutes and were aided by a red card to City's Ismail, but despite a couple of nearly moments in the home penalty box, the game ended in disappointment for the travelling fans.
Bradford: O'Donnell, P O'Connor, Mellor, Wood, Devine (Cooke 68), Richards-Everton, Pritchard, Palmer, Connolly (Ismail 68), Vaughan (c) (A O'Connor 90), Donaldson
Subs not used: Hornby, Gibson, Anderson, Oteh
Cobblers: Cornell, Harriman, Goode, Turnbull, Martin, McWilliams, Lines, Adams (Wharton 73), Hoskins, Warburton (Waters 67), Williams (Oliver 54)
Subs not used: Fisher, Pollock, Kaja, Smith
Referee: Leigh Doughty
Cobblers fans: Not given