It is a topic that shadowed tennis in 2024 and is still a talking point as the 2025 Grand Slam season opens at the Australian Open on Sunday (Saturday EST): doping and the cases involving Jannik Sinner — which actually is still not fully resolved — and Iga Swiatek.
Both spent much of last year at No. 1, and Sinner still will hold that spot in the ATP rankings when he steps on court at Melbourne Park to begin the defense of his championship, one of two major trophies he won over the past 12 months.
