The Hammers won 2-1, with a late penalty coming after a controversial VAR call.
Lopetegui later said, "Happy for the three points. We are happy for the fans and players, they deserve this victory after suffering a lot in the first half. Second half we changed different things and the first half was for them but the second was for us. We were able to compete better and win the match.
"We had some players with yellow cards so we changed at half time because we wanted to be aggressive. I wanted to put Crysencio Summerville on I thought he was key in second half. His energy and his way to play in the second half allowed us to get the goal. Fortunately we won. We keep positive when they scored and the commitment we appreciate the support from the fans.
"Each week I can make changes, thinking of ideas how to play against the opponent. I was thinking today Summerville could be key in the second half but he will play a lot. He did well, we are happy for him and for the team and players and fans."
On the penalty, he said: "I didn't see it. The players say it's a penalty and the referee says it is a penalty so I am sure they are right. But I haven't seen it. I prefer to highlight that after they scored we keep the energy and positive momentum to win the match. I prefer to keep that energy.
"We had a bad result last week but that can happen and today we've won against a big team. To win any match is a big challenge it's difficult you have to go to the limits. We have to keep the energy to compete and be better."