The Hammers were beaten 3-1 on Saturday night.
Lopetegui said, "There were not a lot of good moments.
"We have to do a lot better and a lot of much better things to win the matches, so that’s why I told the players the demands will be higher and we have to try to translate this in the next three weeks.
"We have to analyse this match with calmness, but always knowing that sometimes this is not a bad thing that this happens in the pre-season, because I want us to know more about our needs, and for us to know we have to align and work together for the first match in the Premier League that is more or less in three weeks.
"It is not an excuse because in football both teams have the same conditions, for us and for Wolves too, so we have to adapt.
"Sometimes you play with these conditions and other times you play in minus-five, so it is all about football.
"I think that the more important thing is to analyse what we have to improve with and without the ball and after to work very hard to achieve all these things and to be able to arrive in the first match against Aston Villa.
"It was not the best conditions for the supporters because they suffered the rain too.
In the end they could see the match with a two-hour delay, but unfortunately we could not give them a victory. We hope to change this for them in the next days."