(Editor's note: This article was originally published in 2025 and has been updated following Fleetwood Town's triumph on Tuesday.)

A case can be made that Fleetwood Town's shock penalty shootout win over Arsenal is the biggest upset in League Cup history.

There have been plenty of remarkable boilovers through the years, so it's got competition, but the Gunners entered Tuesday evening's contest as the reigning Premier League champions and with just one loss across 11 league and UEFA Champions League fixtures this season.

Mikel Arteta's side fell behind in the 21st minute when Aaron Loupalo-Bi shook off the attention of Marli Salmon and fired an effort through the legs of keeper Illan Meslier. And while Viktor Gyökeres would pull the visitors back level five minutes into the second stanza and they would dominate possession, the Premier League giants couldn't find a winner inside 90 minutes - forcing the game to penalties.

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Both sides were perfect from the spot until Bruno Guimarães -- just months on from missing a penalty that would have put Brazil 1-0 up in their eventual round of 16 loss to Norway at the FIFA World Cup -- was denied by Fleetwood custodian Jay Lynch.

Teenage defender Conor Haughey then smashed home the winning penalty to spark a pitch invasion as the Cod Army knocked off a side 84 places above them in the English pyramid and claimed possibly the greatest win in their history.

"We talked about Grimsby beating Man United last year; we compared it, even though these are the champions, and thought, if we gave it a go, let's see what happens," Lynch told Sky. "It's amazing for the club, for the club, it means everything to everyone."

It was an evening tinged by a level of madness of all sorts: 16-year-old Max Dowman sent off in the 85th minute after lashing out following a physical challenge from Harrison Neal and play suspended for eight minutes after a drone was flown above the pitch in just the second minute.

"I'm gonna be honest, we haven't practiced once, in terms of penalties," Fleetwood boss Matt Lawlor told Sky. "I'm not gonna sit here and blag you and say we've done some meticulous penalties; we haven't practiced."

It's a result that slots comfortably into ESPN's stockpile of giant killings in the League Cup.

2025 -- Grimsby Town 2-2 Manchester United (12-11 on penalties)

Manchester United hit new depths when they were bundled out of the second round of the League Cup by League Two outfit Grimsby Town in 2025 -- their first ever cup elimination from a side in England's fourth tier.

Down 2-0 at half-time thanks to goals from Charles Vernam and Tyrell Warren, United avoided the ignominy of a regular-time defeat when Bryan Mbeumo and Harry Maguire dragged the game back to parity -- the latter netting his equaliser in the 89th minute -- but then fell after a mammoth penalty shootout.

Then-boss Ruben Amorim apologised to supporters after the game, and he himself became the subject of internet ridicule when footage of him adjusting his tactics board in driving rain was shown on the broadcast, as his side, worth hundreds of millions of pounds, were down 2-0 to a League Two side.

2006 -- Southend United 1-0 Manchester United

Cristiano Ronaldo, Wayne Rooney and Patrice Evra were all on the pitch as holders Man United fell to a fourth-round League Cup exit to Championship strugglers Southend.

A 30-yard free-kick from Freddie Eastwood -- who played 11 times for Wales -- secured the win for Southend against Sir Alex Ferguson's United side that contained 10 internationals.

United went on to win the Premier League that season.

2010 -- Liverpool 2-2 Northampton Town (2-4 on penalties)

League Two Northampton Town completed a scarcely believable upset at Anfield in the third round of the League Cup in 2010.

Milan Jovanovic put Liverpool infront inside ten minutes before Billy McKay and Michael Jacobs put Northampton a goal to the good at 2-1.

David N'Gog scored an equaliser late in extra-time for Liverpool to take the game to penalties where Abdul Osman put away the decisive spot-kick to hand Liverpool -- under Roy Hodgson at the time -- one of their worst ever home defeats.

2012 -- Bradford City 1-1 Arsenal (3-2 on penalties)

Another League Two side -- Bradford City -- dumped out top Premier league opposition in the League Cup quarterfinal in 2012 after beating Arsenal on penalties.

Garry Thomspon put Bradford ahead before Thomas Vermaelen scored in the 88th minute to take a full-strength Arsenal side to extra-time and an eventual penalty shootout against fourth-tier Bradford.

Jack Wilshere and Alex Oxlade-Chamberlain scored their penalties but misses from Santi Cazorla and Vermaelen sent Bradford through.

Current Wrexham manager Phil Parkinson, then of Bradford, went on to lead the side to the final of the competition that year, falling to a 5-0 defeat against Swansea City at Wembley.

2014 -- MK Dons 4-0 Manchester United

Perhaps the most shocking defeat of this list came in 2014 when Louis Van Gaal's Man United were thrashed 4-0 by League One MK Dons in the second-round of the League Cup -- the last time they exited at that stage before their defeat to Grimsby.

Will Grigg and Arsenal loanee Benik Afobe both scored braces at Stadium MK on the way to an untroubled victory for MK Dons against a United team featuring the likes of David De Gea, Jonny Evans and Javier Hernández.

2019 -- Colchester United 0-0 Tottenham Hotspur (4-3 on penalties)

Mauricio Pochettino's Tottenham exited the 2019 Carabao Cup at the third-round courtesy of League Two Colchester -- the lowest ranked side left in the competition.

Christian Eriksen, Dele Alli, Lucas Moura and Son Heung-Min couldn't break down a resolute Colchester as the game went to penalties.

Tom Lapslie scored the winning spot-kick in the shootout after Eriksen and Moura missed for Spurs sending Colchester into the League Cup last 16 for the first time in 44 years.

2019 -- Oxford United 4-0 West Ham

Oxford United manager Karl Robinson called his side's 4-0 victory over West Ham in the third round of the League Cup in 2019, one of the biggest results in the club's history.

Goals from Elliot Moore, Matt Taylor, Tarique Fosu-Henry and Shandon Baptiste gave Oxford the win at the Kassam Stadium over Manuel Pellegrini's West Ham team that started with 10 full internationals.

The match was the second major cup upset Jack Wilshere, who started in midfield, was involved in. He had also started for Arsenal in their defeat to Bradford in the same competition seven years earlier.