Sri Lanka, Oct. 8 -- Cristiano Ronaldo's football career has been a series of glittering firsts, from a record transfer to Real Madrid to scoring more competition goals than any man in history. He's now notched up another huge win off the pitch: becoming the first billionaire player.

During more than two decades at some of Europe's biggest clubs, including Manchester United and Juventus, the 40-year old Portuguese national hasn't been shy about cashing in on his stardom with lucrative side gigs for the likes of Armani and Nike. But it's now, in the twilight of his playing career, that he's been catapulted into the top ranks of the richest sportspeople, inking a fresh contract extension in June with Saudi Arabian team Al-Nassr that's repo...