Iga Swiatek is the second high-profile tennis player to test positive for a banned substance this year, joining Jannik Sinner. While Sinner, currently the No. 1 ranked man, was fully cleared, Swiatek,

The five-time Grand Slam champion has served 22 days of a one-month ban from tennis. Here's what you need to know

Swiatek said a batch of melatonin she used was contaminated with a banned substance, an explanation anti-doping authorities said they accepted after a probe.