The Argentina midfielder was subbed off on 37 minutes as Chelsea ranout 0-3 winners on the day.
Lopetegui later said: "It was a tactical decision to replace Guido Rodríguez, but when a player is replaced before the half it is not the fault of the player.
"It is the fault of the coach, so it is about me and not about Guido.
"Maybe I can do better if I change one player before the half. It is about this and trying to watch myself and not the player in these moments.
"The message for supporters is first to say we are sorry about today.
"We had a big expectation today, and we are going to do all that we can to do our best, to work more and to change things, for sure, because the season is going to be very, very long, very long and I am sure that this team is going to change a lot of things.
"But okay, I think it’s a moment to work, to not talk a lot, and to look forward."