(Photo credit: Jerome Miron-Imagn Images)

Substitute Mikel Merino scored in the first minute of second-half stoppage time to lift Spain into the World Cup quarterfinals with 1-0 victory over Portugal in Monday's round of 16 clash in Arlington, Texas.

Merino's goal six minutes after his insertion takes La Roja to their first quarterfinals since winning their only World Cup title in 2010. They'll next play Friday in Inglewood, Calif., against the winner of Monday's second match between the United States and Belgium.

Portugal's loss likely marks the last World Cup appearance for 41-year-old attacker Cristiano Ronaldo, who had three goals at his record-tying sixth World Cup.

Unlike Argentina's Lionel Messi, who won the 2022 tournament in his fifth appearance and reached the 2014 final, Ronaldo will complete his sixth World Cup without reaching a final. Portugal's best showing during his tenure came via a semifinal run in his 2006 tournament debut.

Merino's winner, his first goal of the tournament after scoring six for Spain in qualifying, came after what was a largely uneventful second half, and from a seemingly innocent restart well beyond the penalty arc.

Fellow substitutes Ferran Torres and Fabian Ruiz combined through the middle to play Merino into the penalty area alone, where his low finish beat the charging Diogo Costa inside the left post.

Dormant for most of the second half, Portugal's attack finally showed signs of life in search of a miracle equalizer. Bernardo Silva came closest to leveling with a header narrowly over the bar six minutes into the added time.

But it would've been undeserved, with Portugal scarcely making goalkeeper Unai Simon work. He finished with only two saves while keeping Spain the only side in this tournament yet to concede.

Spain had the better start. Mikel Oyarzabal missed wide in the ninth minute after an excellent early attack solved Portugal's offside trap, and eight minutes later, Lamine Yamal and Alex Baena forced Costa into a double save.

Portugal grew into the half. Ronaldo forced Simon into a leaping but ultimately comfortable save in the 37th minute, and four minutes later, Nuno Mendes' thunderously struck attempt deflected off Pedro Porro and onto the crossbar.

--Field Level Media