World No. 1 Jannik Sinner is at the peak of his career. The Italian won his second consecutive Australian Open title and third Grand Slam overall on Sunday (January 29).

Tennis fans are expressing their disappointment - but understanding - after Australian Open champ Jannik Sinner announced he won't be defending his title at the Rotterdam Open next week. Sinner won back-to-back Australian Open crowns and his third career grand slam after thrashing Alexander Zverev in Sunday night's final in Melbourne.

And just as Djokovic had a couple of hurdles by the names of Roger Federer and Rafael Nadal to deal with, Sinner is not alone among the newest generation of tennis stars. His top rival at this point is Carlos Alcaraz, who has four Slam victories at age 21 — and won all three matches he played against Sinner in 2024.