The first major test came during a friendly match against Germany's U-19 team, a traditional powerhouse that provided the perfect preparation for the European Championships.
The match was played in a packed stadium in southern Spain, the air thick with anticipation. The German team was a mirror image of their senior counterparts: physically imposing, tactically sophisticated, and ruthlessly efficient.
The first thirty minutes were a tactical chess match, a brutal war of attrition fought in the middle of the pitch. The Germans pressed with a relentless, coordinated intensity, their physicality disrupting Spain's rhythm.
But Mateo, operating as the team's deep-lying playmaker, was an island of calm in the storm. He moved with an economy of motion, his head constantly swiveling, his mind processing the game at a speed that seemed to defy human limitation.
