The hosts were lacklustre in the first half despite Diego Costa opening the scoring in the 10th minute, but second-half efforts from Sergi Roberto, David Silva (2), Vitolo, Costa and a late brace from Alvaro Morata made it a comfortable night for La Roja.
As expected, Spain took immediate control of the possession against the Group G minnows and the hosts took the lead in the 10th minute of action when Costa, who replaced Morata in the XI, headed a Koke free kick past Peter Jehle from inside the Liechtenstein box.
Nicolas Hasler was the player tasked with leading the line for the visitors, but aside from the number 18, nine of Liechtenstein's 10 outfield players spent the opening 20 minutes defending the edge of their own box.
Costa's physicality and willingness to run behind continued to create space for the likes of Silva and Koke, but opportunities were few and far between as Liechtenstein managed to protect their goalkeeper with a solid backline.
The away side's only serious venture forward in the opening half came 10 minutes before the break when Dennis Salanovic delivered from a wide position, but Sergio Ramos turned behind and the resulting corner was cleared downfield.
Vitolo and Sergio Busquets both came close to a second for Spain in the final stages of the first period, but the pair had efforts cleared off the line, before Costa headed a Vitolo cross wide of the post in the 43rd minute.
Nolito replaced Thiago at the interval as Spain looked for more invention in the final third, and only an excellent piece of goalkeeping from Jehle prevented Silva from sending the home side into a 2-0 lead in the 48th minute.
Julen Lopetegui's side came even closer in the 52nd minute when Koke bent a free kick towards the top corner, only for the ball to smash the woodwork as La Roja started to make use of their domination in terms of possession.
Indeed, Spain's second came in the 55th minute when Nolito played a through-ball in to Roberto and the right-back steadied before slipping the ball under the onrushing Jehle.
La Roja had their third in the 59th minute when Silva turned a low Vitolo cross into the back of the net, and it was 4-0 less than one minute later when Costa put one on a plate for Vitolo, who smashed home from close range.
Costa should have made it five in the 63rd minute when he turned and struck towards the bottom corner, but the forward's effort just missed the post. The 27-year-old made no mistake four minutes later, however, as he headed home from close range after seeing his initial strike kept out by Jehle.
Jehle had a torrid time in the final minutes when he let two fairly routine Morata attempts find the back of the net as Spain scored a sixth and seventh before the end of play in Leon.
It could have been nine or 10 for Spain late on, but Jehle kept out a close-range Morata effort, before Silva had a second goal chalked off for offside. Silva was not to be denied though, and completed his brace in stoppage time with a well-placed finish.
Next up for La Roja is a trip to Italy on October 10, while Liechtenstein are in action on the same night at home to Albania.