Luis Diaz and Mohamed Salah (penalty) had Liverpool 2-0 ahead at halftime, but Matheus Cunha's goal helped Wolves stage a second-half rally, though they ultimately fell short.
Pereira said afterwards: "I'm frustrated because our first half was not good. I think we showed a lot of respect to them and we cannot play like this. We must play our game. At half-time, I asked the team to press them in our way and we did a fantastic second half. The second goal was not possible but I think we deserve it.
"The first half was a lot of respect, too much respect. We cannot play football this way. We like to press high and to create chances, have the ball and play with courage.
"Everything I can say now will not change the decision. I have my opinion but I keep it to myself. It is better not to speak about referees.
"Second yellow card, maybe. It would be different but it is what it is. I am not a referee. I am very happy, very proud of my players for what we did in the second half. I don't care if it's Liverpool or another team, it's about my team. I want to see the courage to play. Next time we need to realise that we have quality and we need to play with it.
"Second half was fantastic, I remember Liverpool with a lot of difficulties to stop us."