Arsenal suffered one of the most humiliating defeats in their history as the Premier League champions were stunned by fourth-tier minnows Fleetwood in a League Cup penalty shoot-out on Tuesday.
Mikel Arteta's side crashed out 5-3 on penalties in an incredible fourth round upset after the tie finished 1-1 in normal time.
Arsenal's Bruno Guimaraes had his penalty saved by Jay Lynch in the shoot-out and Conor Haughey scored Fleetwood's winner.
Aaron Loupalo-Bi's first-half goal had put Fleetwood ahead before Viktor Gyokeres equalised after the interval.
Arsenal's 16-year-old rising star Max Dowman was sent off for violent conduct in the closing stages.
Arteta paid the price for prioritising Sunday's Premier League trip to Liverpool as his decision to make nine changes backfired spectacularly.
No one would have predicted Arsenal's embarrassment regardless of Arteta's selection gamble.
They had moved level on points with Premier League leaders Manchester City after a 2-0 victory over Everton on Saturday.
But instead of extending their run of 11 wins from their 13 previous games, Arsenal returned to north London red-faced after a loss that ranks among the darkest days in the club's glittering history.
Arsene Wenger's Arsenal suffered a shock League Cup loss against fourth tier Bradford on penalties in 2012.
Arteta's team were beaten by second tier Southampton in the FA Cup last season and also lost to Nottingham Forest, then in the Championship, in the same competition in 2022.
Supporters of an older vintage will recall Arsenal's 1969 League Cup final loss against third tier Swindon and their 1992 FA Cup exit at fourth tier Wrexham.
But even those painful defeats cannot compare to this remarkable result.
For once, Arsenal fans will not have fond memories of Highbury -- Fleetwood's ground shares the same name as the Gunners' ancestral home before their move to the Emirates Stadium in 2006.
Fleetwood's tiny 5,327-capacity ground -- where goals are celebrated with a burst of children' cartoon song Captain Pugwash over the tannoy -- is a far cry from the famous marble halls and dignified grandeur of Arsenal's former stadium.
Now it will be remembered forever as the site of Arsenal's most chastening loss in the Arteta era.
Fleetwood boss Matt Lawlor wept tears of joy as disbelieving fans flooded the pitch to celebrate their club's astonishing victory.
- 'Cod Army' uprising -
Only Myles Lewis-Skelly and Viktor Gyokeres kept their places from the Everton game, with teenagers Dowman and Marli Salmon starting, while 18-year-old winger Ceadach O'Neill made his debut.
Languishing in 18th place in League Two, Fleetwood had lost their previous two league games against Exeter and Cheltenham, yet they showed no signs of being intimidated by their illustrious visitors.
After an eight-minute delay due to an unauthorised drone flying over the stadium, Arsenal were caught cold on a windy night by the Irish Sea.
Fleetwood are nicknamed the 'Cod Army' in reference to the town's fishing industry, so it was somewhat fitting that a mistake from Salmon netted their opener in the 21st minute.
Salmon's lack of experience was brutally exposed when Loupalo-Bi muscled his way past the 17-year-old with ease, racing into the penalty area to plant a low finish past debutant keeper Illan Meslier.
Arsenal monopolised possession after that shock, but Arteta grew visibly agitated with their lack of cutting edge.
Arteta sent on Martin Odegaard at half-time and Gyokeres bagged Arsenal's equaliser five minutes later.
It was a scrappy effort that left Fleetwood feeling aggrieved as Gyokeres wrestled with his marker before poking O'Neill's ball past Lynch from close-range.
Dowman saw red in the 85th minute, dismissing for kicking out at Harrison Neal after a strong challenge from the Fleetwood midfielder.
Although it looked a harsh decision, Arteta was unimpressed with Dowman, giving him a stern word as the midfielder trudged off.
Both teams scored their first three penalties in the shoot-out, but Guimaraes was denied by Lynch and Haughey held his nerve to seal the biggest shock in League Cup history.