India, Dec. 18 -- The last time Carlos Alcaraz met Jannik Sinner in a tennis match, the Spaniard ended his post-match speech with a warning. "Hope you're going to be ready for next year," the world No.1 said after losing to Sinner in the title clash of ATP Tour Finals last month. "Because I will be."

A bit of light-hearted banter, perhaps, between the two biggest names in men's tennis at the moment. But it told a brief story of all the work and effort the players put in during the off-season - a prized phase between the last major event of the season and the first week of the new year. A period dedicated to vacations, reflection, analysis, preparation and a reset.

But now Alcaraz, the most unpredictable player on court, has made the mos...