India, July 27 -- It was April 1, 2019, just another All Fools' Day in our strange world. Algerian president Abdelaziz Bouteflika faced massive protests after nearly 20 years in power; British parliament voted against four Brexit alternatives; and a US judge rejected a plan by Donald Trump to send asylum-seekers to Mexico. Amid this global churning, in the Mediterranean port city of Alicante, two teenagers faced each other for the first time, in the opening round of a nondescript Challenger tennis tournament. From Sexten, Italy: Jannik Sinner, 17. From Murcia, Spain: Carlos Alcaraz, 15. The encounter would mark the start of two fairy-tale storylines: distinct yet connected, separate yet intertwined. Let's call it Sincaraz Day. Six years lat...