Fernandes struck twice for the first-leg 3-0 Europa League semifinal win, with the first from the penalty spot.
"You need to grow and understand where you are, the place you play for and club you play for," he told TNT afterwards.
"United is a global club, it’s unbelievable the attention we get, the pressure we get, everything.
"But it’s football, it’s what we love to do. I feel the pressure with every penalty, I feel the pressure.
"I think that's the good thing about football, it’s what we have to enjoy because when I finish my career that pressure will go away and I will be much more relaxed."
Incredible numbers from midfield
Fernandes now has 19 goals and 18 assists for the season - and the midfielder says he wants more.
"I want to score, I want to assist," continued the Portuguese.
"It’s a big part of my game, I need to take that responsibility because I know since I came to the club, and even before, the club bought me because I scored 32 goals in one season.
"They knew I could create, I could score, and I just need to keep delivering, because if you want to be at the highest level, you have to keep delivering."
Fernandes added: "The result for us is unbelievable. We could in the first half get that result and then in the second half control the game. I think we should push a little bit more in the second half, be that little bit quicker on the ball to go forward, but we controlled the game and that is good."