India, July 19 -- When Argentina and Spain walk into the World Cup final, the contest will carry the usual weight of nations, histories and contrasting footballing cultures. Argentina are attempting to defend the title that completed Lionel Messi's career. Spain, European champions and arguably the tournament's most assured collective, are seeking to establish the beginning of another era of dominance.

Yet the final's most compelling tension is concentrated in two players separated by two decades.

Messi, 39, returns to football's greatest match as Argentina's captain, creative centre and enduring source of inevitability. Lamine Yamal, who turned 19 during the tournament, arrives as the most electrifying representative of a generation th...