Wolves striker Matheus Cunha admits the players are "upset" after their 1-0 defeat at Manchester United on Monday night.
Raphael Varane headed home the winner on 76 minutes before United goalkeeper Andre Onana clattered into Sasa Kalajdzic late on only to escape punishment.
Cunha said: "Upset is the word. We worked a lot. We need to keep improving. We mixed the new ideas and the old ideas. I'm a little upset with that result.
"He [Gary O'Neil] has helped us a lot. It's hard to change the coach one week before the first game but football is like that.
"I feel 100%. The Premier League is the best competition in the world. I feel more free to play here. Today we needed to score more.
"It's a very hard decision. For me it's a penalty but you need to respect."