MELBOURNE, Australia -- Serena Williams, Naomi Osaka and Victoria Azarenka withdrew from tuneup tournaments just days before the Australian Open is set to begin in Melbourne Park.
Williams on Friday pulled out of her semifinal match against top-ranked Ash Barty at the Yarra Valley Classic, citing a right shoulder injury.
"I feel pretty good," Williams said Saturday. "I've gotten a lot of treatment already on my shoulder. But I'm super confident it's going to be great. I'm feeling very confident, I think is a better word, and getting ready for hopefully the next two weeks."
"It's definitely something that I'm going to have to deal with for the fortnight," she added. "Kind of knowing that going into a tournament definitely helps. Also knowing, okay, I'm going to have to probably pick up some different therapy exercises after each match. It's going to be really important."
No. 3-ranked Osaka pulled out of her Gippsland Trophy semifinal against Elise Mertens, citing a "niggling injury." Azarenka withdrew from the Grampians Trophy quarterfinal match against Anett Kontaveit with a lower back problem.
Williams usually doesn't play in a tournament in the week before a Grand Slam event, but she made an exception before last year's US Open and for this Australian Open because of all the disruptions caused by the COVID-19 pandemic.
The 39-year-old American was playing her first tournament since withdrawing from the French Open before her second-round match because of an Achilles tendon injury in October. She, like all players traveling to Australia for the tournament, had to quarantine for 14 days and had limited practice during that time.
With the year's first major scheduled to start Monday, Williams might be better off resting. She and Osaka are set to play on the same half of the draw at the Australian Open.
"Sorry to Tennis Australia and the fans to have to withdraw today," Osaka said. "I have a niggling injury and in light of the [Australian Open] on the horizon, I need to be cautious. I look forward to competing next week."
Osaka's withdrawal gives Mertens a walkover into the final.
Williams had three wins at the Yarra Valley Classic -- one of six tournaments at Melbourne Park this week -- culminating with a 6-2, 4-6, 10-6 win in a match tiebreaker over Danielle Collins on Friday.
The withdrawal came after her postmatch news conference -- when she made no reference to any issues -- so no full explanation was offered.
It means Barty gets a walkover into the final and will also get some rest Saturday.
There were 70 matches on the order of play Friday, an expanded program a day after all matches in six tournaments were postponed so that 160 players and 507 people overall could isolate and undergo testing because a worker at a quarantine hotel returned a positive test. Tennis Australia said all tests were negative.
To speed things up a little at the back end of the tournament, 17 courts were being used and women's matches were reduced to two regular sets with a 10-point match tiebreaker if required.
Williams and Barty both had to play the match tiebreaker -- Barty beat Shelby Rogers 7-5, 2-6, 10-4.
Before withdrawing, Williams said she was looking forward to the semifinals.
"It's definitely a good opportunity to see where I'm going against the current No. 1, that's really important for me," Williams said. "Obviously, I think for her, as well, to see where she's going against my game.
"It's been a long 12 months. Tennis has been played but not really, so ... hopefully this is like a new year where things will be different."
Garbine Muguruza beat defending Australian Open champion Sofia Kenin 6-2, 6-2 to advance to the semifinals, reversing their result of their 2020 final at Melbourne Park. She will next play No. 8 Marketa Vondrousova.
The Associated Press contributed to this report.