When the World Cup kicks off next month, the two biggest stars in Qatar will be Cristiano Ronaldo and Lionel Messi, the players who have defined the modern era of the world’s most popular sport and together achieved a level of fame normally reserved for popes and U.S. presidents.
The rivalry between a diminutive genius from Argentina and a preening superhero from Portugal has played out over the last 15 years as a tale of opposites, right down to the most important tools of their trade: their cleats. With billions of dollars at stake, Mr. Messi wore Adidas, while Mr. Ronaldo was Nike.