New-look Blackpool began brightly with Jack Redshaw at the heart of their best moves but Northampton created the early chances. Sam Hoskins shot against the near post and Dominic Calvert-Lewin headed just over.
Chris Hackett swept Cobblers into a 20th minute lead when he converted David Buchanan’s low cross from just inside the box.
Calvert-Lewin doubled Northampton’s advantage four minutes later when Blackpool failed to deal with Hackett’s low cross and the on-loan Sheffield United striker turned well to beat Kyle Letheren from 10 yards.
Hoskins increased Northampton’s lead in the 29th minute when Blackpool failed to deal with Lawson D’Ath’s low cross and he beat Letheren at the second attempt after his initial effort had been blocked.
Redshaw should have reduced the arrears when he mis-kicked from close range with the goal begging and Kwame Thomas was unable to force the ball home.
Joel Byrom and Ryan Cresswell went close after the restart and Calvert-Lewin almost doubled his tally. Thomas missed Blackpool’s best chance but they offered little in the final third.