The Red Devils continued their improved form with victory on penalties against Arsenal in the FA Cup at the weekend and Fernandes knows the importance of consistently strong performances.
The United captain told Sky Sports: "We just have to understand that if we can keep this level, this performance, and most importantly these results the fans will be behind us.
"We can deliver, they have seen it, we have to prove that we can deliver every three days. We will do it, and we need them to be behind us to do it."
Fernandes revealed that the team are desperate to win the FA Cup again after their unexpected triumph last season ended a challenging campaign on a positive note.
The Portuguese international said: "We know how big Arsenal is and how big the rivalry between the clubs is. For us it was just about getting through to the next round as we know we want to get to the end of this competition.
"It is really important for the club, and we saw last season the feeling of winning and we want to repeat it. We know to repeat that you have to beat the best teams, we did it yesterday and hopefully we’ll keep doing it."
Fernandes explains that United's recent improvement stems from their belief in manager Ruben Amorim's approach.
He said: "It’s really easy when you don’t get results, when you don’t get performances to start disbelief in everything you’ve been doing.
"That’s a good thing about the team is that we kept belief on what we are doing, how we are training and where we want to go as a team and what we want to improve as a team. Every time you lose, or something goes wrong everyone has an opinion on what you should do differently.
"Obviously, the manager has his own idea, and he really believes in this, so there is no way that he makes you not believe it. Everything he says to you, everything he tries to pass you, he does it in a way that we really believe in what we are doing. Even in games where you concede a goal or have a setback, he just wants us to understand that the things we are doing will result if we do them in the right way.
"That’s the most important thing."
