Morgan Gibbs-White, Chris Wood and Taiwo Awoniyi struck the goals for the visitors at Molineux.
Pereira said afterwards: "You can say that we were unlucky but for me, we created chances to score but we faced a team that were physically strong, we felt that on the pitch. They were very fast on the counter-attack and when they score first, they are a team that they are compact and wait for mistakes.
"Each mistake we made, they scored a goal. They scored at the end of the first-half in a moment where we could have equalised. We didn't and this is not luck. Sometimes you can say luck but I thought their goalkeeper made fantastic saves. We need to improve our details inside the box to score more goals."
On what positives he can take from the match, he continued: "A lot of things. I am happy with my players. They tried everything to take something from this game but this is also something we are expecting. We cannot lose our balance in the moment when we lose the ball. When we lose the ball, if we are not balanced, they are strong in the counter-attack. We prepared for this in training but in the end, we had a lot of players out in a small squad and we tried our best.
"I am proud of the players because they tried everything. We tried everything to get a different result but with a small squad and the problems we faced during the week - it was very difficult to be more competitive than today."