The two best men's players in the world are reconfiguring the sport before their opponents' eyes. They don't know what to do about it

When Carlos Alcaraz is on court for a training session, perhaps working on his newly revamped service motion, he's doing so to buttress a game already good enough to claim four Grand Slam titles. He's also got his young rival,

With two-thirds of the Big Three retired, a pair of young stars are building a special rivalry on the ATP Tour as a new year gets underway.