Slaven Bilic’s side faced a daunting task against the world champions after their 7-0 annihilation at the hands of England on Saturday, but they certainly rose to the challenge early on here after the inquest that followed their heaviest-ever defeat.
They took a deserved 17th-minute lead through Ivan Perisic, as Mateo Kovacic picked out Igor Matanovic, whose initial shot was saved by Unai Simon before the PSV Eindhoven forward headed home the rebound.
Spain’s defence has been far from watertight in this Nations League campaign after conceding just once en route to glory in North America, as Simon almost gifted the hosts a second. His pass was intercepted by Nikola Vlasic, who teed up Matanovic, but La Roja shot-stopper made amends with a fine save.
The visitors were frustrated by this spirited Croatia team, but could have twice restored parity seconds before half-time through Mikel Oyarzabal and Lamine Yamal.
That served as a sign of things to come after the restart, with Dani Olmo’s diving header inches away from meeting Lamine’s cross before the visitors found an inevitable equaliser in the 61st minute.
Half-time substitute Merino was the man to provide it, as Olmo set up the ball perfectly for the Arsenal midfielder to sweep home a clinical left-footed finish after Josip Stanisic’s headed clearance was intercepted.
Luis de la Fuente’s side were eager to turn the game on its head, and Lamine was not too far away from doing so when his effort deflected wide of the far post.
But Spain’s defensive frailties came to the fore again, and Perisic took advantage of a misplaced pass by Martin Zubimendi with an opportunistic strike that was kept out by Simon.
However, the 37-year-old’s evening was over just moments later after receiving a second yellow card for a challenge on Marc Cucurella, as Croatia’s defence braced themselves for a barrage of Spanish attacks.
But just when the Vatreni looked to be edging their way towards a hard-earned point, Zubimendi teed up Merino with a pass which his Arsenal teammate effortlessly took into his stride and rifled an unstoppable left-footed strike past Dominik Livakovic.
The result leaves La Roja firmly in charge of Group A3 with four wins from as many games, while Croatia succumbed to consecutive defeats despite a much-improved display after that harrowing England defeat.
Flashscore Man of the Match: Mikel Merino (Spain)