Spain advanced to the World Cup quarter-finals and ended Portugal's tournament with a 1-0 victory decided in the dying seconds of the Round of 16 clash. Mikel Merino struck in the 90th minute to separate two evenly matched Iberian rivals and send La Roja through at the expense of their neighbours.

For most of the contest, defences held firm. Portugal and Spain traded possession and probed for openings, but neither side could find the breakthrough as the clock wound toward what looked certain to be extra time. The backlines on both sides were disciplined and compact, and clear-cut chances were at a premium in a tense knockout affair where one mistake could prove fatal.

That mistake, or rather that moment of quality, arrived with virtually no time remaining. Merino, who had controlled Spain's midfield tempo throughout the evening, appeared at exactly the right moment to convert and send a wave of relief and euphoria through the Spanish contingent. The goal was as decisive as it was late, leaving Portugal no time to respond.

Merino was rightly named man of the match with a rating of 7.7, having dictated play from the middle of the park for the full 90 minutes before delivering the killer blow himself. His composure on the ball and positional intelligence gave Spain a persistent edge in the midfield battle, and he capped his performance with the only goal of the game.

For Portugal, it is a bitter exit. A clean sheet was within their grasp for so long, and the prospect of extra time seemed the likeliest outcome entering the final minutes. To concede so late, with barely a chance to kick off again, is a cruel way to leave a World Cup. Their defenders will wonder what more they could have done across 89 minutes of solidity.

Spain march on, their reward a quarter-final berth earned through patience and a refusal to accept a stalemate. The victory underlines their capacity to find solutions under the most intense pressure, and Merino's composure in front of goal at the death is the image that will define this tie for years to come.