Spain booked a blockbuster semi-final meeting with France after beating Belgium 2-1 thanks to last-gasp specialist Mikel Merino in Los Angeles.
The substitute arrived in the 88th minute to pounce on an error from stand-in goalkeeper Senne Lammens, who was a late introduction himself after Thibaut Courtois was forced off injured, turning home the rebound from Pau Cubarsi's opportunistic strike.
The moment was as excruciating for Lammens as it was exhilarating for Merino, coming up clutch again after also scoring a late winner in victory over Portugal in the last round. He had only been on the pitch for 117 seconds, scoring with just his second touch.
Spain had been breached for the first time at this World Cup in the first half, when makeshift No 9 Charles De Ketelaere headed Timothy Castagne's teasing cross beyond Unai Simon to cancel out a well-worked opener from Fabian Ruiz.
But Luis de la Fuente's side were not to be denied, Merino, so often Arsenal's saviour, refusing to stand down. For club and country, he continues to offer solutions in big moments, his only touch in the Belgium box resulting in the decisive goal.
Spain remain unbeaten since March 2023, a remarkable streak of 37 matches, and will play tournament favourites France in a tantalising tie in Texas on Tuesday for the right to contest the final. De la Fuente has now managed more games at major tournaments without losing than any other international manager (13).