Fernandes held his nerve to fire home from the spot 10 minutes into added time, securing a 3-2 win for Ole Gunnar Solskjaer's side.
And he credited the role played by Fred, revealing he had been able to keep his focus because the Brazilian midfielder had kept protesting Brighton players away from him. "As everyone starts shouting, discussion and VAR and everything, I try keep away, take the ball and try and keep the focus," said Fernandes.
"I saw the keeper taking his bottles and everyone, the towel came out, so I was just taking the ball, waiting, 'focus on what you have to do'.
"Of course, sometimes we say you have to have b***s to take a penalty like this.
"I know everyone trusts in me, everyone expects me to score, and it was a big part of the game like I said.
"Penalties are key in some games and today was key. Doesn't matter if I score, or if someone else scores - what matters is the three points we're taking home.
"After we had the penalty, everyone was fighting for everything: 'penalty, no penalty'. We kept the focus until the end. I felt the trust of everyone behind me.
"I see Fred fighting with everyone who was coming to take out my focus, taking away the players from Brighton."