Naomi Osaka, a four-time major champion seeded No. 2, withdrew after one match — and a conflict with Grand Slam officials over a rule that mandates speaking to the media — to take a mental health break. No. 1-ranked Ash Barty, the 2019 champion, retired from her second-round match with a left hip injury. No. 3 Simona Halep, the 2018 champion, never showed up because of a hurt calf. Serena Williams was beaten in the fourth round. Defending champion Iga Swiatek lost in the quarterfinals.