Fernandes says United's players must prove they have the mentality to succeed with the club.
"The reality is to play here you have to have that pressure, you have to have the balls to play for this club — that is what it is," Fernandes said.
"You have to feel that in every moment in every game it is a new chance to bring us back to the position we deserve.
"Unfortunately for us this season there have been too many ups and downs and every time we look like getting there, we get punched again and go down.
"What we have to do is every time we take a punch and go down, we must get up and try to punch back."
On manager Ruben Amorim declaring them the "worst team in the club's history" after last Sunday's defeat to Brighton, Fernandes continued: "I don't want to hear my manager saying certain things about the team because I know he doesn't feel it.
"But he made himself part of that and when the manager makes himself part of what he's saying, no one can get angry or disappointed by it.
"When he says 'the worst team in Manchester', he speaks about the position we are in and when you look at where we are in the league we are in the worst position we've ever been.
"So you have to take it, that's the reality unfortunately. We are in this position for a long time and the club doesn't belong there.
"But we have to accept that and understand we need to push ourselves to much bigger things and higher positions."