Madrid, Sep 6 (IANS): Spain crushed Liechtenstein to assure themselves of one of the two Group G tickets to the 2018 football World Cup and Serbia bolstered their position atop Group D, but the contest grew tighter in Group I, where four teams are vying for the two available spots.

La Roja, fresh from their impressive win over Italy in Madrid, jumped out to a 3-0 lead in the first 15 minutes of Tuesday's eight-round match in Vaduz and went on to prevail 8-0, reports Efe.

Alvaro Morata and Iago Aspas each scored a brace for Spain, who move to 22 points, three points ahead of Italy with two qualifying rounds to go.

The Italians beat fourth-placed Israel 1-0, while Albania posted a 1-1 draw with Macedonia to boost their point total to 13.

Serbia triumphed 1-0 away to Ireland, taking the lead in the 55th minute on a goal by Aleksandar Kolarov and preserving it to the final whistle despite playing the last 20 minutes with 10 men after Nikola Maksimovic was sent off.

The victory brings the Serbs to 18 points, four ahead of Wales, who bested Moldavia 2-0 to leapfrog Ireland into second place in Group D thanks to goals from Hal Robson-Kanu and Aaron Ramsey.

Austria and Georgia deadlocked 1-1 in the other Group D match.

Tuesday's results left the top four sides in Group I separated by just two points.

Croatia, starting the day in first place with 16 points, fell 1-0 to Turkey, who climbed to 14 points and now share third place with Ukraine.

The Croatians remain on top of the group, by only by virtue of a better goal differential than Iceland, who got two goals from Gylfi Sigurdsson to beat Ukraine 2-0 and boost their point total to 16.