Spain's Diego Costa (C) celebrates his goal with teammate Sergio Ramos during the match between Spain and Liechtenstein at the World Cup 2018 Qualifying European Zone in Leon, Spain, Sept 5, 2016. [Photo/Agencies]

MADRID - Spain enjoyed a comfortable and convincing 8-0 win over Liechtenstein in their opening qualifying game for the 2018 World Cup finals thanks to an avalanche of second half goals.

Diego Costa put the Spanish ahead after just 10 minutes of the game and scored his side's fifth of the night to justify coach Julen Lopetegui's decision to play him ahead of Real Madrid striker Alvaro Morata.

Costa was allowed a free header from Koke's free kick and flicked the ball in at the far post.

Liechtenstein were getting nearly every one of their players behind the ball, looking to close the Spanish down in their own half and that meant that although Spain controlled the ball, clear chances were at a premium although Koke should have scored in a penalty area scramble in the 40th minute.

The second half began with Spain laying siege to the Liechtenstein goal and it was only a matter of time before the goals arrived.

The second of the night was supplied by Sergi Roberto after a pass from Nolito, who had come into the game replacing Thiago Alcantara.

That opened the floodgates and a third goal didn't take long to arrive as Vitolo crossed for David Silva to score from close range after 58 minutes and a minute later Vitolo scored the fourth as Silva returned the compliment.

Costa added a fifth in the 67th minute as Liechtenstein's heads began to drop, shortly before he was replaced by Morata, who duly scored the sixth of the night with a left foot shot after a well-worked passing move in the 82nd minute and then the seventh with a shot the keeper should have kept out.

Silva scored Spain's eighth of the night in injury time to complete the rout.