India, July 18 -- When Lionel Messi leads Argentina onto the pitch at the New York/New Jersey Stadium, he will be up against a legacy he helped forge running through a different shirt. He will be taking on a Spain playing a modern version of the possession-first philosophy he once perfected at Camp Nou. In the World Cup final on Sunday, he will look to prove he can beat the very idea that shaped him.

Cut Spain open and you'll find FC Barcelona at the core. Eleven of Spain's 26-man squad either play for Barcelona's first team or came through its famed La Masia academy. It's the blueprint Spain relied on during their golden era between 2008 and 2012, when a Barca-heavy squad, led by Iniesta and Xavi, won back-to-back European Championships...