Manchester United's Carabao Cup campaign came to an embarrassing end as League Two club Grimsby Town produced one of the competition's greatest upsets.

United fought back from 2-0 down to level the scores at 2-2 after extra time before losing 12-11 in the penalty shoot-out, with expensive misses from summer recruits Bryan Mbeumo and Matheus Cunha.

Goalkeeper André Onana made only one save as Grimsby kept their nerve.

Amorim Slams Players for Negative Attitude

Carabao Cup: Ruben Amorim Blasts Manchester United Players For Poor Carabao Cup: Ruben Amorim Blasts Manchester United Players For Poor
DARREN STAPLES/AFP via Getty Images

According to AOL, this loss was the first-ever Carabao Cup tie defeat to a fourth-division side, and it came as their earliest elimination since 2014.

Following the surprise result, manager Ruben Amorim spared no words. He publicly lashed out at his team's poor concentration and questioned their dedication.

"The way we started the game, we were not even here. When everything is so important in our club, everything that happened, it's a problem in our club, we should do so much better," Amorim said.

Amorim acknowledged that Grimsby were the worthy winners, emphasizing that United's issues transcend the result. He continued that his players shouted very loudly with their performance, and that needs to change.

Warning Signs for United's Season

United's poor beginning to the Premier League, picking up only a single point from two games, was already raising alarm among fans. This defeat only increased these anxieties. Even after investing more than £200 million in signings this summer, Amorim indicated that problems within the team persist.

According to ESPN, Amorim said that United cannot play like their last match, especially it's against a fourth-division club. He added that it's all about the attitude and mentality throughout the game.

For a club that survives on medals, crashing out so early is a massive blow. Amorim accepted the pressure of expectations on United and admitted that his team did not live up to those standards.

Little Time to Feel Pressured

The defeat leaves United with uncomfortable questions over their direction under Amorim. With a key Premier League tie looming, the Portuguese manager has little time to calm the waters.

For supporters, the hope is that this humiliation is a wake-up call before the season careens further.