Andy Morrell fired the visitors into a first-half lead but a freak equaliser - when goalkeeper Rhys Evans totally misjudged an innocuous looking long-range effort by Eoin Jess - allowed the Cobblers to stretch their unbeaten run to five matches.
Blackpool looked comfortable until Evans suffered his fatal misjudgement, but from that moment it was the home side who were the likelier winners with top scorer Scott McGleish firing against the crossbar, while substitute Andy Kirk firstly scraped the paintwork with a low curling shot before volleying another decent chance over the crossbar.
Blackpool's goal arrived when home defender Luke Chambers lost possession and neat interplay between Blackpool's man of the match Wes Hoolahan and Keigan Parker allowed Morrell to coolly slot the ball past Mark Bunn from ten yards.
The Cobblers almost drew level with a rising angled drive by Jason Crowe which was tipped over by Evans, while the lively McGleish managed a header wide from a long throw by a David Hunt.
Hunt's delivery into the box from long throws was proving a potent weapon and McGleish had another header saved from one of them shortly after the restart.
But the complexion of the game changed in the 62nd minute when the speculative effort by Jess clearly had Evans expecting an interception on the ball. Instead, nobody managed a touch and it sneaked beyond the goalkeeper's reach.
Morrell was always a handful from the home defence, but having had one header cleared off the line in the first half he almost bagged his second a minute after his side had been hauled level, instead curling an effort wide.
Most of the fireworks came at the other end but Northampton, who were anxious to cash in on their first home win of the season a week earlier, were unable to make their greater possession count in the final analysis.