Bruno Fernandes instigated Lisandro Martinez's brief switch to centre forward towards the end of Manchester United's epic FA Cup tie with Arsenal.

Fernandes alerted United head coach Ruben Amorim to an issue with Martinez, who was struggling to run in the final minutes of extra time.

With United players' workload increased after Diogo Dalot's sending off in the 61st minute, the team clung on for a 1-1 draw to trigger a penalty shootout that United won 5-3.

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Amorim decided to move Noussair Mazraoui from left wing back to left centre back, with Toby Collyer moved to right wing back in a 5-3-1 formation, while Joshua Zirkzee dropped into midfield as Martinez went up front.

"I think it's a team effort," Amorim said. "And Martínez could not run anymore in the backline. Bruno Fernandes said that he was really tired.

"And then in the backline if you have one ball, you are dead. So it's better to change, like Martínez there. So the first point was Bruno. Then the second point: we changed.

"Amad was doing the defending and Toby (Collyer) in front. And then my assistant says let's change it. So I changed it. So it's like a team effort. It's not me.

"Everybody was paying attention to the game. And we tried to maintain the results. Tried to go to penalties. So it was a team performance in all aspects."

United host Southampton in their first home game of 2025 but have lost their past three home fixtures to Nottingham Forest, Bournemouth and Newcastle.

Southampton are at the foot of the Premier League with only one win and a meagre six points. After two uplifting performances and results away to Liverpool and Arsenal, Amorim reiterated there are no excuses ahead of United's most winnable match of the campaign.

"For me, there are never excuses," Amorim added. "So we have to accept when we had a bad performance. When the opponent is better.

"But in the small details, I think it's really clear for everybody. If we are the same team that we were against Liverpool and Arsenal we will be a better team against any opponent."

Amorim clarified it is his problem if United's performance level plummets again. "It's also my problem. I'm trying to help them to understand that. But we have to do it as a team. But I think it's clear. Everybody can see that in some games we are a different team. We have to be really consistent on that. I'm trying to do the same things. To explain the strengths and the weaknesses of every team.

"And then tomorrow we have to perform. And we have to understand that the expectations are bigger. We have to have more ball. We have to control the game more. And that sometimes is harder to play against these teams."