Manchester United sank to a new low under Ruben Amorim by getting eliminated by fourth-tier Grimsby Town after a marathon penalty shootout in the second round of the English League Cup on Wednesday.

Grimsby won a dramatic shootout 12-11 at the 9,000-capacity Blundell Park, with Bryan Mbeumo missing the decisive penalty. United needed late goals by Mbeumo and Harry Maguire just to salvage a 2-2 draw in regulation, having trailed 2-0 at halftime.

It will go down as one of the most embarrassing results in United's history and leaves the team winless in three games so far this campaign, after a woeful 15th-place finish in the Premier League last season.

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It is the first time Man United have ever been eliminated from a cup competition by a team from England's fourth tier. While United have been knocked out by nonleague teams when there were just two divisions in England, the most recent of those was in 1914 in the FA Cup against Swindon Town.

"It's an amazing feeling, one that will live on forever," said Grimsby's Charles Vernam.

Vernam scored to put Grimsby into a shock lead before United youth product Tyrell Warren capitalized on goalkeeper André Onana's latest error to double the home side's lead before halftime.

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Grimsby had chances to pull further ahead in the second half, only for Amorim's side to seemingly snatch a late reprieve and force a penalty shootout.

Onana saved new signing Clarke Oduor's spot kick and Matheus Cunha blew the chance to win it for the visitors, with the goals continuing until Mbeumo thumped his effort off the crossbar as fans poured onto the pitch.

"Going into the penalty shootout, the gaffer (manager) said to us, 'Lads, all the pressure is on them,' and it was really," Grimsby midfielder Kieran Green said.

The home team is currently fourth in League Two, and finished the match with a lineup containing several academy graduates and a Faroe Islands international.

United, meanwhile, had £200 million ($270 million) worth of new signings just in its attack in Mbeumo, Cunha and Benjamin Sesko. Cunha also failed in the shootout by having his weak attempt saved.

The result piles more pressure on Amorim, who came into the game with 16 wins from his 44 matches in charge of United after being hired last November.

United were only playing in the second round -- for the first time since 2014 -- after failing to qualify for European competition last season. That year, the team lost 4-0 at third-tier MK Dons in the second round.

Information from The Associated Press, PA and ESPN Research was used in this report.