Darren Carter was sent off on his debut as the Cobblers succumbed to a last-gasp defeat at York City.
Town looked to have done enough to secure a creditable 0-0 draw at Bootham Crescent but former Sixfields loanee Ryan Jarvis had other ideas, scoring in the game’s 90th minute.
The nature of the loss, and particularly the timing of the decisive goal, suggests that while many of the personnel may have changed, there remains plenty of work to be done before the travel sickness of last season will be cured.
Northampton gave debuts to six players, and it was an error in midfield gave York the first sight at goal, Ashley Chambers forcing a good low save from Matt Duke after being slipped in by Tom Platt.
Chambers should have scored on the 25-minute mark when he weaved inside from his wing but failed to make a good contact with a shot that landed tamely in Duke’s waiting, low hands.
Danny Emerton had Northampton’s first good chance, flashing a volley wide after a brief game of head tennis in the York City penalty area.
The first half ended in the same way it had been played, with York on the front foot.
After a dubious corner, the ball was worked to Craig Clay, whose shot was parried out by Duke in the direction of Cresswell, who fouled Collins in attempting to reach the rebound.
Then Chambers sliced inside Kevin Amankwaah and looked certain to score before Heath got across to block his poked effort.
Northampton were much more lively after the break and Roy O’Donovan showed a good first touch and plenty of bravery to muster a rising volley than cannoned down off the crossbar and out at the end of a swift counter-attack down the right.
The visitors survived a penalty appeal midway through the second half when Cresswell went down under contact from Ben Tozer, whose reaction suggsted he thought the striker had dived - the referee agreed.
They were not so fortunate moments later, though, when Carter, who had already been booked, was shown a second yellow for a foul on Platt.
The midfielder looked like he got a toe on the ball as he stretched to make the challenge, and was incensed as he exited down the tunnel.
With a man less, the Cobblers’ attack was always likely to be diluted, although O’Donovan had a couple of good efforts at goal - one blocked, one over - in the immediate aftermath of the red card.
The game looked certain to end as a goalless stalemate but York had other ideas.
A corner was cleared as far as Lanre Oyebanjo, who fed Chambers down the right from where he hung a dangerous cross into the box.
Cresswell’s presence caused confusion and the ball spilled out to Jarvis, who rattled home a shot on the bounce to give the home side all three points.
York City: Ingham; Oyebanjo, Smith, McGurk, Davis; Puri (Bowman 77), Clay, Platt, Chambers; Jarvis, Cresswell
Subs not used: Kettings, Parslow, Coulson, Montrose, Fyfield, Allan
Northampton: Duke; Amankwaah, Heath, Collins, Widdowson; Emerton (Hooper 90), Tozer, Carter, Deegan, Morris; O’Donovan
Subs not used: Demontagnac, Snedker, Moyo, Dias, Toney
Away fans: 642