MELBOURNE, Australia >> 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, Jannik Sinner, in mind.

“The good thing for me is, when I’m seeing him winning titles, when I’m seeing him in the top of the ranking, it forces me to practice even harder every day. In practice, I’m just thinking (about) the things that I have to improve to play against him,” Alcaraz said Saturday, a day before the start of the Australian Open. “That, I think, is great for me: Having him (and) such a great rivalry, so far, just to (force me to) give (my best), every day.”

Alcaraz, 21, and Sinner, 23, head into the 2025 tennis season at the top of the men’s game, coming off a year that portended greatness for both. With Rafael Nadal now joining Roger Federer in retirement, leaving 24-time major champion Novak Djokovic as the lone remaining member of the Big Three on tour, it appears as though Alcaraz and Sinner have separated themselves from the rest of the next generation, each taking two of the four Slam singles trophies in 2024.

Forever, it seemed, the sport’s most important laurels were dominated by Federer, Nadal and Djokovic, and anyone harboring hopes of claiming then needed to defeat at least one, and often two, of that trio.

The names have changed, but the dynamic is similar.

“I feel like now, with Jannik and with Carlos, it kind of moved toward the same way, just with new guys. You have to go through them to win big tournaments. It’s as simple as that,” said Alexander Zverev, a two-time major finalist who is seeded No. 2 at Melbourne Park, between No. 1 Sinner and No. 3 Alcaraz. “They both won two Grand Slams (last) year. And they’re the two best players in the world, for sure. And you have to beat them to win the tournament.”

Sinner is the defending champion in Australia, and went on to also win the U.S. Open in September, part of a season in which he went 73-6 with eight titles — but also dealt with a doping case in which he tested positive twice for trace amounts of an anabolic steroid, blamed it on accidentally being exposed to a banned substance via a massage from his trainer and was exonerated. (The World Anti-Doping Agency appealed that ruling; a closed-door hearing will be held at the Court of Arbitration for Sport in Switzerland on April 16-17.)