Wigan became the first FA Cup winners to be relegated from the top flight in the same season after a 4-1 defeat to Arsenal at the Emirates Stadium sent them down.
Shaun Maloney's free-kick sent Wigan into half-time on terms after Lukas Podolski had given Arsenal the lead.
But hopes of a dramatic escape were washed away by a flood of catastrophic defensive lapses as Arsenal struck three times in eight minutes through Theo Walcott, Podolski and Aaron Ramsey.
Wigan lurched painfully from triumph to despair just three days after winning the FA Cup for the first time in their history with a 1-0 win over Manchester City at Wembley.
Owner Dave Whelan now faces losing not only his club's top flight status, but his manager Roberto Martinez and leading players including Maloney and Callum McManaman.
They are marooned in 18th place, four points behind Sunderland and five behind Aston Villa whom they play on the final day - those two clubs can breathe long sighs of relief after a trying season. Wigan join QPR and Reading in the Championship.
Arsenal now need a win at Newcastle on Sunday to guarantee fourth place and Champions League football at the expense of North London rivals Tottenham Hotspur.
Martinez banned alcohol after Wigan's Wembley triumph, but Arsenal attacked vigorously from the off in search of a Cup final hangover and found their opponents - metaphorically at least - reaching groggily for the Alka Seltzer after 72 hours of celebration.
Walcott, effervescent down the right wing, crossed for Santi Cazorla who nipped in front of his marker but headed wide of the right-hand post.
Wigan found themselves under the sort of pressure Manchester City could not muster and soon cracked in miserable fashion.
Cazorla delivered a corner from the Arsenal left and Podolski somehow found himself completely unmarked as he headed the bouncing ball in from six yards.
Roberto Martinez's side barely had a kick, let alone a shot, in the first haf-hour, but they gradually came into the game through the ever-lively Maloney and McManaman.
Maloney won and scored the equalising free-kick amid controversy - the Scot appeared to back into Mikel Arteta as he was tackled but Mike Dean penalised the Arsenal captain.
Maloney punished him with a beautiful free-kick that flashed over the wall and into the right corner of the net.
Wigan needed victory to maintain any realistic chance of survival and continued to attack after the break - however without the injured Maynor Figueroa their awful defending cost them dear.
On 63 minutes Antolin Alcaraz failed to cut out a Santi Cazorla cross and Walcott stole in to finish from close range.
Shortly afterwards Podolski grabbed his second after Paul Scharner played him miles onside, allowing the German to collect a headed Cazorla through ball and lift the ball past Joel Robles.
Ramsey then drove the final nail in the coffin, dribbling inside from the left, deceiving Joel with his eyes and finding the far corner from a tight angle.
Poorly as Wigan defended, the damage was done well before tonight - though Martinez still emerges from this season with credit, he will wonder how a side capable of such heroics could end up in the second tier.
MAN OF THE MATCH
Theo Walcott (Arsenal): Not the most consistent, but Wigan's obligation to attack provided him with space to attack, particularly in the second half when he took a more central role.
ARSENAL: Szczesny 7, Sagna 6, Mertesacker 7, Koscielny 6, Gibbs 8, Rosicky 7, Arteta 6, Ramsey 7, Cazorla 7, Walcott 8, Podolski 8... Subs: Vermaelen N/A, Wilshere N/A, Oxlade-Chamberlain N/A.
WIGAN: Joel 6, Alcaraz 5, Scharner 4, Boyce 6, McArthur 6, Espinoza 5, McCarthy 5, Gomez 6, McManaman 6, Maloney 7, Kone 6... Subs: Di Santo 6, Watson 6, Henriquez N/A