The stunning finish at SoFi Stadium sets up a tantalizing showdown between European champions Spain and the tournament favorites France and the red-hot Kylian Mbappe in Dallas on Tuesday.
But it was heartbreak for Belgium’s substitute goalkeeper Senne Lammens, sent on late, who spilled a shot into the path of Merino.
The dramatic finale came after Fabian Ruiz had opened the scoring for Spain, before Charles De Ketelaere grabbed one back for Belgium against the run of play before halftime.
Welcoming Kevin De Bruyne and Jeremy Doku back to the starting XI, Belgium were rocked by a hamstring injury during the warm-ups to captain Youri Tielemans that hit them hard.
Having already lost Amadou Onana to a ruptured ACL, the Red Devils would have to play a near second-choice midfield against the Spanish possession masters.
Ruiz, brought in for Pedri, wasted no time combining with Rodri to dominate the ball and Barcelona’s teen sensation Lamine Yamal curled an early shot just wide of the far post.
But opposing winger Doku was bright for Belgium, cutting in from the left to feed De Ketelaere, the striker fresh from his brace against the United States on Monday.
Still, it was Spain who struck first. On the half-hour mark, Pedro Porro played a sharp one-two with Lamine Yamal before expertly cutting it back from near the byline to Dani Olmo.
Olmo’s shot was parried by Thibaut Courtois, but fell to Ruiz, who fired it home.
Suddenly it was all Spain. They pinged passes around the Belgian half as though this World Cup quarter-final was a training exercise, laid on for an A-list crowd featuring Brad Pitt, Penelope Cruz and Noel Gallagher.
But Belgium, having fought back astonishingly late from 2-0 down in the round-of-32 to dispatch Senegal, did not panic.
They grabbed one back in the 41st minute. De Bruyne slid a through ball wide to Timothy Castagne. His cross found De Ketelaere, who perfectly timed his run and outmuscled Barcelona youngster Pau Cubarsi to head home.
It was the first goal Spain had conceded this World Cup.
Improbably, Belgium almost grabbed another before half-time. Breaking from a Spain corner, De Ketelaere’s pass to a totally clear Doku was barely intercepted by Olmo.
Yamal grew into the game after the break, nearly finding Mikel Oyarzabal with an incisive cross that was well blocked by a charging Courtois.
Belgian coach Rudi Garcia brought on veteran striker Romelu Lukaku, who had scored from the bench in three straight games.
The game opened up. A Belgian cross hit Rodri’s arm but the impact was deemed accidental. Oyarzabal had a shot saved from a close, tight angle.
A tearful Courtois was forced off by injury after 70 minutes. He was replaced by Lammens, the 24-year-old Manchester United ‘keeper making his World Cup debut in daunting circumstances.
It turned out to be a nightmare.
In the 88th minute, Cubarsi shot low from range, and Lammens should have held onto the ball. Instead substitute Mikel Merino was first to the rebound, smashing it home.
It was the Arsenal midfielder’s second straight late winner from the bench, after he scored the crucial goal against Portugal in stoppage time on Monday.
Late on Alexis Saelemaekers rounded Unai, but was unable to find Lukaku in front of an open goal.
As the whistle blow, Courtois came out to embrace a distraught Lammens, while other members of Belgium’s ageing “Golden Generation” stood immobile and disbelieving.
For Spain there were embraces and fist pumps, before attention quickly turns to their blockbuster clash with France. (AFP)
