Bailey Peacock-Farrell was called into action after only two minutes, with the Birmingham City loanee getting a fingertip on the ball to stop a deflected Tyrese Fornah shot from finding the back of the net.
Shortly after, the Cobblers midfielder issued Steve Bruce’s side with another warning. On this occasion, the former Derby County man placed his effort just wide of the post, after powering his way into the box.
Down the other end, Lee Burge was on hand with a double save to keep the Seasiders out. After stopping Danny Imray’s initial effort, the 32-year-old denied Albie Morgan on the rebound as well.
As part of the same move, Josh Bowler went down under pressure in the box, but the decision went against him, with the referee booking the winger for simulation.
Following the restart, both sides had their fair share of half chances, without anything more ever coming.
Peacock-Farrell was required to come off his line to stop Cameron McGeehan after space presented itself to the midfielder in the box, while Bowler saw a shot deflected over the bar, following some good work down the right from Danny Imray.
Shortly after, Burge was called into action by Jordan Brown, but the shot was pretty much straight at the keeper - who punched away the danger.
Northampton were able to find the back of the net in the 67th minute, before their celebrations were cut short, with a foul being given on George Honeyman before McGeehan fired towards goal.
The 30-year-old wouldn’t be denied with his next shot on target, as he edged his side in front inside the final 10 minutes.
After finding himself with space in the box, the former Luton Town man was able to slot past Peacock-Farrell – in what proved to be the difference between the two teams.
Here’s how the Seasiders performed:
1. How did the Seasiders perform?
Blackpool travelled to Sixfields to take on Northampton Town. Photo: Gareth Evans
2. Bailey Peacock-Farrell- 6
Bailey Peacock-Farrell made an early reaction save to stop a deflected effort from Tyrese Fornah, and made a couple of further stops beyond that. Photo: Gareth Evans
3. Danny Imray - 7
The early signs of Danny Imray's time with Blackpool have been positive. After producing an impressive display against Bolton, the fullback was a rare bright spark at Sixfields as well. Photo: Gareth Evans
4. Michael Ihiekwe - 6
Michael Ihiekwe did make some positive contributions, but the Seasiders defence looked shaky once again. Photo: Gareth Evans
5. Olly Casey - 6
Olly Casey won some important duels, but Blackpool's problems as a collective at the back once again proved costly. Photo: Gareth Evans
6. Hayden Coulson - 5
It was an afternoon where Hayden Coulson was limited in his attacking contributions from left back. Photo: Gareth Evans