La Roja will host Costa Rica on Saturday night, before taking on World Cup hosts Russia next week.
Lopetegui has claimed that Costa Rica "are one of the better sides in world football", while the head coach is also looking forward to taking on Russia as the 2010 world champions build towards next summer's tournament.
"Our focus is on the only thing that interests us, the World Cup," Lopetegui told reporters. "We have only two international breaks to fine-tune things for Russia, and we'll be facing two teams that will demand a lot from us.
"They'll force us to have two great performances. We'd like to have more breaks, but it is what it is. Costa Rica? They're a very good team and are one of the better sides in world football.
"They came a penalty shootout away from the semi-finals in Brazil after they won a group that contained England, Italy and Uruguay. They've kept that unit and style of play, and Russia play in a similar way, so these games can come in handy."
Spain played out a 2-2 draw with Colombia in their last international friendly back in June.