Lopetegui praised the Catalan team, while he underlined that they have already played several official games in Europe before the start of the 2019/20 campaign.
"It will be difficult, because Espanyol have already accumulated four official matches," Lopetegui told the press.
"We will have to have a very good match and have to play a great game at all levels.
"Espanyol have worked well, they are solid, and they have good players.
"We must be a team in every sense and show everyone a great version [of ourselves], because Espanyol are a very good team.
"It is clear what to do on the field and we will be required to demonstrate ambition and enthusiasm."