Spain boss Julen Lopetegui has said that Alvaro Morata "should be fit" to face Liechtenstein in La Roja's opening 2018 World Cup qualifier on Monday night.

Morata, who returned to Real Madrid from Juventus this summer, was substituted in the first half of Spain's 2-0 win over Belgium on Thursday night after appearing to suffer a thigh injury.

However, Lopetegui has insisted that the change was purely "for precaution" and has tipped the centre-forward to be fit to lead the line against the Group G minnows in Leon.

"Morata suffered a hit and he was about to feel a muscular problem, so we decided to change him for precaution," Lopetegui told reporters. "Fortunately, he is alright and he should be fit to play the next game."

Diego Costa was Morata's replacement during the comfortable win over Roberto Martinez's Belgium.