Spain is advancing in the World Cup on the strength of a defense that has recorded six consecutive clean sheets, with goalkeeper Unai Simón going 609 minutes without conceding in tournament play. This focus on defensive solidity is a departure from Spain's stereotype of free-flowing, interchangeable attacking players and reflects a contemporary shift in football strategy.

Coach Luis de la Fuente, who previously managed Spain's under-19 and under-20 teams, has consistently emphasized structure. His defensive approach is exemplified by the central defensive partnership of Aymeric Laporte and 19-year-old Pau Cubarsi. Cubarsi, who debuted for the national team at 17, has earned praise for his composure and anticipation.

Albert Puig, who coached Cubarsi from age 12, noted the defender's exceptional ability to anticipate play, stating, "Where other players might improvise, Pau is so focused that he can anticipate by a second or two." Xavi, Cubarsi's first manager at Barcelona, highlighted his calmness on the ball, saying, "When Cubarsí has ​​the ball, my heart rate doesn't go up. That is his greatest strength."

While Laporte brings experience, Spanish analysts like Santi Ovalle suggest Cubarsi is emerging as the leader of the defense. This partnership has been key, with targeting Laporte more than Cubarsi in their recent match against Portugal. The defensive unit is further bolstered by defensive midfielder Rodri, who provides a shield for the back line and can drop between the center-backs to form a three-man defense when necessary.

The effectiveness of Spain's defense is also evident in their ball distribution. Ahead of the quarter-finals, Rodri had made the most accurate passes in the tournament (499), followed by Cubarsi (432) and Laporte (397). Cubarsi had also sent more balls into the final third than Portugal's Bruno Fernandes.

Simón's goalkeeping has been exceptional, surpassing Walter Zenga's all-time record of 517 World Cup minutes without conceding, set in 1990. The team's structure and defensive discipline are reminiscent of their 2010 World Cup victory, which was secured through a series of 1-0 wins.

A potential weakness for Spain appears to be the absence of a world-class center forward. Alvaro Morata was not included in the squad, and other strikers have struggled to convert chances, as seen in a missed opportunity against Portugal. Lamine Yamal, while showing flashes of brilliance, has not yet consistently set the tournament alight, possibly due to a recent hamstring issue that affected his preparation.

Despite these considerations, Spain's defensive resilience presents a significant challenge for opponents. As a Spanish newspaper noted, "Dos centrales y un destino" – two center-backs and one destiny – underscoring the pivotal role of their strong defensive foundation. The team is set to face Belgium in the Los Angeles quarter-final.