Jubilant Grimsby

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.

Grimsby's jubilant fans stormed onto the field to celebrate with the players after Mbeumo's spotkick rebounded off the crossbar to seal United's fate.

"It's an amazing feeling, one that will live on forever," said Grimsby's Charles Vernam, who scored one of the team's goals.

The Mariners currently sit fourth in League Two, and finished the match with a lineup containing several academy graduates and a Faeroe Islands international.

United, meanwhile, had 200 million pounds ($270 million) worth of new signings just in its attack in Mbeumo, Matheus Cunha and Benjamin Sesko. Cunha also failed in the shootout, seeing his weak attempt saved, and Sesko took United's 10th penalty — only one ahead of Onana.

After Onana and Grimsby goalkeeper Christy Pym converted their penalties, the shootout reverted to the outfield players once again. Bruno Fernandes scored his for United, but Mbeumo couldn't.

"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.

It was bittersweet for Pym, who said with a smile: "I'm a Man United fan, so I'm half-fuming a little bit."

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 in November. He sat in the dugout during the shootout, not even watching the spotkicks.

A 1-0 loss to Arsenal in the opening round of the Premier League featured an encouraging performance by a new-look United team, but some worrying old habits returned when fading to a 1-1 draw at Fulham on Sunday.

Agencies