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,

The first round of the Australian Open continues on Monday at Melbourne Park where top seed and defending champion Jannik Sinner seeks a third Grand Slam title while Novak Djokovic begins his quest for a record-extending 25th major.

Novak Djokovic begins his bid for Grand Slam history on a blockbuster Monday at the Australian Open as Jannik Sinner starts the defence of the trophy he won 12 months ago. Carlos Alcaraz also gets underway out on day two as he looks to lift the one major title to elude him.

Italy's Jannik Sinner returns the ball to Netherlands' Tallon Griekspoor during the Davis Cup final tennis match between Netherlands and Italy at the Martin Carpena Sports Hall in Malaga, southern Spain, Sunday, Nov. 24, 2024. Credit: AP/Manu Fernandez

Novak Djokovic is heading into the Australian Open with new optimism as he targets his 25th Grand Slam title in Melbourne, but he will face a slide down the ATP Rankings if his recent trend in form continues.