Substitute Mikel Merino scored a late winner to put Spain in the quarter-finals with a 1-0 victory over Portugal and end Cristiano Ronaldo’s World Cup career.
The European champions will face the United States – the only one of the co-hosts remaining – or Belgium on Friday in Los Angeles.
In front of an expectant crowd of 70,649 at the air-conditioned home of the Dallas Cowboys, a match that on paper promised so much failed to really deliver.
Extra time looked certain, before fellow substitute Ferran Torres slipped in Merino to settle the contest in the first minute of injury time.
It meant a sour final World Cup match for the 41-year-old Ronaldo, now playing in Saudi Arabia, having confirmed on the eve of the encounter that this would be his last dance on football’s biggest stage.
The neighbours came into the contest both unbeaten, but while Portugal had not been entirely convincing, Spain had not even conceded a goal in the tournament.
One of the pre-tournament favourites, they still haven’t.
For all their pedigree, talent and history, Spain have only lifted the World Cup once, in 2010, while Portugal’s best was third place in 1966.
In Ronaldo and Spain’s 18-year-old Barcelona prodigy Lamine Yamal, the last-16 showdown was touted as a showcase of two extraordinary talents at opposite ends of their careers.
There was a sombre moment shortly before kickoff when a black-and-white image of the late Portugal forward Diogo Jota flashed up on the giant screen that looms over the field.
