Ruben Amorim says Manchester United need another attacking wing-back like Amad Diallo to become better playing in his system.
The United boss came under fire for refusing to adapt in Monday's dismal defeat to 10-man Everton at Old Trafford, bringing his 3-4-2-1 formation back into the spotlight ahead of Sunday's trip to Crystal Palace, who have enjoyed success playing in the same shape.
Amorim, chasing a goal against Everton after Idrissa Gueye's red card, replaced left wing-back Patrick Dorgu with Diogo Dalot, naturally a full-back, in a like-for-like change that left United devoid of any attacking threat down that side.
Palace's attack-minded wing-backs, Daniel Munoz and Tyrick Mitchell, have been a cornerstone of Oliver Glasner's success, while United only have Amad Diallo in that mould and Amorim admits that will have to change for the team to improve.
Asked if wing-back is an area he wants to strengthen, Amorim said: "We need time to improve the characteristics of the team. I've said that over the last year.
"To give an example, in the last game [against Everton], we should have an Amad with the right foot to put on the other side to play against 10 men.
"It is these characteristics that in time we will try to get to be a better team. If we are the perfect set-up to play in this way, not yet. But like any team, we need time to put the right characteristics into every position."
The United boss dismissed direct comparisons with Palace ahead of Sunday's game but acknowledged Glasner's side are outperforming them at the moment as they sit in 10th.
Although Palace are fifth in the table, they are only two points better off than United, who could go above them with a win at Selhust Park.
"We play in a different way. You can understand that by data. It is hard to explain everything. They are a different club and they are doing things better than us. That is quite simple.
"You don't say that all 4-3-3 teams play in the same way. We play in a different moment, we defend in a different space, we attack in a different way. They are just doing things better than us."
Glasner defends Amorim system
Glasner defended Amorim's system ahead of the game and said he had seen an improvement in United this season.
"It's really funny talking about the 3-4-3 system, and I think United have the highest xG in the Premier League for scoring goals," Glasner said.
"Their team has changed. Especially in attack. They needed more goals and they invested £200m, buying three players up front. Also, now they have players who can play very intense like [Bryan] Mbeumo.
"For me, it's impressive to see. We compared it [their last meeting] to where they are now. I think their work-rate is much higher than it was last year and then they get the reward."
Amorim 'has question to answer' over wing-back decision
Amorim admits he would have preferred to bring on a more attacking alternative to Dalot at Everton with no other options available on his bench, but stuck with the same shape nonetheless.
It was a decision that enraged Sky Sports pundit Gary Neville on co-commentary.
"Ruben Amorim has a question to answer," he said. "Bringing Dalot on over there in front of Luke Shaw? I don't quite see it. You have five at the back, why? Embarrassing.
"This should be like the Alamo. Really quick, high-tempo passing side-to-side, getting into good wide areas, putting crosses in, getting bodies in attack, sustaining attacks. It's very slow from United. There is no presence in the box whatsoever."
Sky Sports pundit Jamie Carragher, speaking in the Monday Night Football Studio, also criticised Amorim over his inflexibility.
"Ruben Amorim feels like the first manager I've seen who sticks with a system rather than an idea of how to play," Carragher said. "It feels like the formation is his baby and to not change it or alter it in certain situations like that [against Everton], I don't understand how you can stick with it so steadfastly.
"It's not about losing the three points against Everton, I think it is one of those moments where people will really question the manager. He will take a lot of the blame."
Analysis: Amorim's underperforming wing-backs
Sky Sports' Nick Wright, Adam Smith and Oliver Yew:
At Sporting, Amorim's wing-backs were attacking outlets vital in making his system work. In his final full season in charge, in 2023/24, Nuno Santos, Geny Catamo and Ricardo Esagio, his three most-used wing-backs, contributed a combined total of 26 goals or assists between them in league games alone.
Amorim's wing-backs at Manchester United have contributed half as many goals or assists across a similar number of league games.
And nine of their 13 goals and assists, roughly 70 per cent, have come from Amad Diallo, with the others used in the position, Dorgu, Dalot, Noussair Mazraoui, Harry Amass and Tyrell Malacia, only managing four between them in a combined 67 starts at wing-back.
The struggles of Amorim's wing-backs raise further questions about Amorim's devotion to his system. If they are not contributing offensively, then what are they really bringing to the table? It is just one of many questions for their under-fire head coach.