Spain boss Julen Lopetegui has paid tribute to his team's professional performance in Tuesday night's 8-0 victory over Liechtenstein.

La Roja, who remain three points clear of Italy at the top of Group G, took another big step towards securing qualification for the 2018 World Cup after scoring eight unanswered goals in Vaduz.

"The difference between the national teams was huge and we did what we set out to do," Lopetegui told reporters. "We wanted to play like a serious team and kill the game off early... We achieved that with [Sergio] Ramos's goal.

"After that, we scored a second, which gave us the necessary calmness to play how we did. Scoring in the first minute gives you that calmness, which paved the way for us."

Next up for Spain, who need four points from their final two fixtures to guarantee first spot in the section, is a home game against Albania on October 6.