January's defiant display in north London felt like being a turning point for the Portuguese but instead proved to be a false dawn

The last time Manchester United faced Arsenal was probably the highlight of the Ruben Amorim era. Just one week after holding runaway Premier League leaders Liverpool to a draw at Anfield – and almost beating them – the Red Devils took on the second best team in the country over the past three years and knocked them out of the FA Cup on penalties.

It truly was a spirited performance, playing with one man down for an hour after Diogo Dalot's sending off. It was a day rich in narrative: Alejandro Garnacho set up Bruno Fernandes' goal days after it was revealed the club were willing to sell him, Altay Bayindir produced some stunning saves during the 120 minutes after a harrowing previous appearance in north London at Tottenham, while Joshua Zirkzee scored the decisive penalty barely two weeks after being dragged off in the first half at Old Trafford to cheers from his own supporters.

The result was hailed as the great turning point for Amorim, the platform on which the team's revival under the Portuguese coach would be built. But three months on from that defiant display at the Emirates Stadium, as United prepare to meet Arsenal again on Sunday, the great resurgence under Amorim is yet to take place. United are still 14th in the Premier League table but the gap between them and the top-four has widened to 14 points, while there are nine points between them and the top half of the standings. United have also been knocked out of the FA Cup by Fulham, with their good fortune in penalty shootouts running out.

Their only chance of salvaging the season lies in the Europa League but their chances of winning it look slim after failing to see off an unremarkable Real Sociedad in the first leg of their last-16 tie, ending a game in which they had been the better side clinging on for their lives. So why were Amorim's side unable to build on the momentum of that memorable win at Arsenal?

Getty Images SportNot delivering on Fernandes' pledge

Speaking on the pitch at the Emirates Stadium moments after the shootout win, Fernandes said the performances against Arsenal and Liverpool had proved that his side were capable of taking on anybody. The captain also urged his team-mates to show the same hunger in every match, beginning in their next game at home to basement club Southampton. "I know we want to celebrate and everything, but our focus is now on Southampton – that is when we have to back it up," he said.

"The big games against Liverpool, Arsenal, everyone steps up because it is a big game. We suffered a lot but we sacrificed as a team, and at the end you get this. You want to be in these kinds of games, you want to be involved, you want to be the best but we have to do it in Old Trafford with these fans again. We have to give it back to the club. We need to do it every week, every game."

Fernandes' team-mates could not live up to that pledge, though, and in their next 12 games since beating Arsenal United have won six, lost four and drawn twice. In the league their record is three wins and three defeats from seven.

AdvertisementGetty Images SportRelegation form

United ended up beating Southampton but it was anything but straightforward as they conceded numerous chances before falling behind to a Manuel Ugarte own goal. They were trailing until the 83rd minute and relied on a sublime late show from Amad Diallo to get them out of trouble. It was a victory but there was an air of disbelief around Old Trafford that the team had made it so hard for themselves and in their very next game against Brighton they sunk to a 3-1 defeat. They did manage to pull off three consecutive wins against Rangers, Fulham and FCSB, ending January with a creditable five victories from six games.

But February was a miserable month, beginning with a home loss by Crystal Palace which also saw Lisandro Martinez tear his knee ligaments and leave the pitch in tears. More injuries followed soon after following a disastrous week of training in which Amad damaged his ankle ligaments and was ruled out for several months while Kobbie Mainoo strained a muscle and was ruled out for several weeks.

It meant United were down to the bare bones for their trip to Tottenham, naming eight teenagers with no senior experience on the bench. Unsurprisingly, they suffered a 12th defeat of the season, their highest number of losses at the same stage since they were relegated in 1974.

GettyMissing Amad & Martinez

The most obvious explanation for why United have not been able to kick on since the Arsenal win has been the injuries, both short-term and long term. Of the 16 players that got on the pitch during the FA Cup tie, only nine were able to face Real Sociedad on Thursday. And two absences have stung more than any other: Amad and Lisandro Martinez. Amad was the team's new talisman, having contributed to 12 of the 28 league goals the team had scored when his injury struck. The timing could hardly have been worse as United had recently loaned Antony to Real Betis and Marcus Rashford to Aston Villa, leaving them with only one wide forward in Alejandro Garnacho.

Losing Martinez was also a massive blow. The Argentine is not only the team's most combative defender, he is a valuable source of passes into attack. And he is a mentality monster, his infectious thirst for winning livening up the rest of the squad. Without him, there has been a noticeable lack of hunger.

Mainoo's absence has been less significant as Amorim does not appear to completely rate him and the club are still open to selling him amid reports he will not sign a new deal. And yet he is still one of the most talented players in the squad, with his injury having deprived Amorim of a cool head in midfield and forced the coach to lean more on Casemiro.

Getty Images SportLow confidence

United also seem to be suffering from a severe crisis of confidence. This is on an individual level, with Rasmus Hojlund on a 19-game goal drought and Alejandro Garnacho failing to score since November, and on a collective level, with the team seeming to lack belief in each other. Take Dalot failing to pass to Hojlund against Real Sociedad when the striker would have been clean through on goal, or several players growing frustrated with Andre Onana's errors and his poor distribution.

Amorim has not really helped foster belief in the squad. After the FA Cup tie at Arsenal he said: "I believe in them every time. I want to push them. Sometimes I challenge them and they don’t like because they are not used to it, but I will continue to do that." Amorim's idea of 'challenging' his players has included calling them the worst team in the club's entire history and making disparaging comments about the departed Rashford and Antony. He has also undermined players through his selection choices, such as when he fielded Mainoo up front against Palace ahead of Zirkzee and Hojlund.

The Portuguese is not exactly creating an "us against the world" mentality which underpinned Sir Alex Ferguson's great sides. Indeed, it often feels like the coach is waging a war against his own team.