It was a disappointing performance from Jon Brady’s men, who never truly got to grips with an impressive home team.
Vale were full of running, energy and attacking invention, pinging the ball around with confidence, with Brady admitting his team was ‘suffocated’.
Alfie Devine, Oliver Arblaster and the impressive Funso Ojo were at the heart everything the home side did, and although the Cobblers defended well and limited the amount of clear-cut chances, they were eventually worn down.
Substitute Ben Garrity was the man to break the deadlock, firing home a 20-yard strike five minutes from time.
Town were left to rue Sam Hoskins passing up their best chance just a matter of minutes earlier, but in truth the home side deserved their victory.
Here are our player ratings from an off-day at Vale Park...
5. Patrick Brough
On a day where the Cobblers were not seen anywhere near enough as an attacking force, Brough was arguably the biggest threat, breaking down the left. Set up Town's two best chances in the second half - including the big one for Hoskins at 0-0 ... 7 Photo: Pete Norton
6. Jack Sowerby
The midfielder has been in very good form, and tried his best to get things going at Vale, carrying the ball when getting the chance. But like his midfield team-mates, he found himself too often outnumbered and overrun... 6 Photo: Pete Norton
7. Marc Leonard
The Brighton loan has rarely, if ever, been less influential in a Cobblers shirt. Worked hard enough but couldn't grab any sort of control. Where he normally sets the tempo, he had no real answers the one set by an impressive Vale team... 5 Photo: Pete Norton
8. Mitch Pinnock
A frustrating day for the normally creative Pinnock, who simply wasn't allowed the time or space to weave his magic. Again, no doubting his work-rate or commitment, but this was an off day... 5 Photo: Pete Norton