Northampton have been relegated from League One after losing 3-0 to Blackpool.
The Cobblers only gained promotion through the play-offs in June but made an immediate return to League Two as Luke Garbutt's early goal and a late brace from Jerry Yates all-but secured Blackpool's place in the play-offs.
Northampton made a bright start but were behind after 19 minutes when Garbutt collected Yates' pass and drilled a fine finish into the bottom corner.
Ellis Simms sliced well wide when under pressure before Jonathan Mitchell made a strong block one-on-one against Yates.
Danny Ballard's header at the start of the second half was headed off the line by Michael Harriman before Mitchell saved well from Kenny Dougall.
Blackpool were dominant and they sealed their victory 14 minutes from time when Mitchell fumbled a shot and Yates was on hand to score the rebound.
Yates still had time to score his second with a close-range finish four minutes from the end.
Brady 'deeply hurt' by relegation
"I'm deeply hurt by today now that we have been relegated, because I honestly believed from the outset that we could do it and I never gave up believing," said Northampton interim boss Jon Brady.
"It's been very personal for me because we're local and we threw everything at it. It hurts a lot at the moment and it's very raw and it'll take a bit of time to get over this.
"But in football you've got to pick yourself up, dust yourself down and look to put a marker down at Sunderland next weekend to say that this club won't lie down."