Federico Valverde scored a first half hat-trick for Real although a penalty save from Gianluigi Donnarumma against Vinicius Junior offers City slight hope for the round 16 second-leg.
Speaking after the 3-0 defeat, Bernardo said: “At 3-0 it makes it a bit more difficult.
“Now it feels really bad, now it feels really dark. Tomorrow is another day and for sure next week we will go to the game thinking we have a chance.
“Right now is the moment to reflect and see what we didn’t do right. Then next week when we are preparing we will be hopeful we can do something.
“It is difficult to speak about it because I would need to watch it again. My feeling on the pitch was that we started the game well.
“The environment we could not control and I think my team let the emotions change the game.
“We felt comfortable and were finding the right spaces but after conceding the first one we lost completely the control, we stopped controlling transitions and second balls.
“When you play against Real Madrid with the quality they have, you pay the price.”