Jamie Carragher highlights the one 'BIG mistake' Ruben Amorim has made as Man United boss since derby win that has left the club in a 'really poor position'

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Jamie Carragher has revealed what he believes to be the biggest mistake Ruben Amorim has made since taking over at Man United.

Having earned a reputation as one of Europe's most promising young managers for his various successes at Sporting Lisbon, Amorim was appointed as Erik ten Hag's successor at Old Trafford in November.

The 39-year-old signed a two-and-a-half year deal upon arrival, with the club maintaining an option to extend for an additional twelve months.

Amorim was tasked with turning United's fortunes around after they slumped to their worst-ever Premier League start after winning just three of their opening nine games when Ten Hag was relieved of his duties.

The Portuguese endured a mixed start that saw a draw with Ipswich and a win over Everton followed by back-to-back league defeats against Arsenal and Nottingham Forest.

United appeared destined for a third successive league loss when they were trailing 1-0 in a clash against Man City, before late goals from Bruno Fernandes and Amad Diallo secured a momentus win.

Jamie Carragher highlighted what he believes to be the biggest mistake of Ruben Amorim's tenure at Man United

The former Liverpool defender claimed the decision has proven costly for 39-year-old

Just days after the derby victory, Amorim selected a rotated side for an EFL Cup quarter-final with Spurs with five changes made to the team that beat City, a decision Carragher claimed proved costly for United's momentum.

'Listen, when a new manager comes in, I think we give them a little bit of slack,' the former Liverpool defender said on Sky Sports.

'We understand it's not easy. He's coming in with a different system.

The one big mistake he made I feel was the team he picked at Tottenham, and not necessarily through the fact that it was to win the cup.

'On the back of the Manchester City result, they had to keep the momentum going.'

United would ultimately be knocked out of the competition in a dramatic game plagued by individual errors on both side.

Ange Postecoglou's side looked comfortable with a 3-0 lead before United mounted a comeback but were unable to capitalise on their initiative and lost 4-3.

Carragher continued: 'You look at those results there and win some, lose some, you win the derby and the way they won it as well was fantastic.

Amorim led United to a memorable comeback win over rivals Manchester City earlier this month

But Carragher insisted the decision to field a rotated side in defeat Spurs days later ultimately halted the club's momentum

'The buzz from Manchester United fans in the stadium watching at home, they've beaten Pep Guardiola, the biggest rivals, and then you go to Tottenham.

'He didn't need to change the team as much, and he needed to just keep that going.

'Then you look where they are now, three defeats in a row, and it feels like they're in a really poor position.'

United went on to lose three successive Premier League games, leaving the club 14th in the table heading into Monday's clash with Newcastle.