The meeting ended with the score 4:6, 6:3, 7:6 in favor of the US representative.
The match lasted 2 hours and 18 minutes.
Osaka is the winner of the Australian Open 2021.
In the next round of the competition, 20-year-old Anisimova will fight with the current world number one, Australian Ashleigh Barty.
Earlier it was reported that Azarenka defeated Svitolina and reached the 1/8 finals of the Australian Open.