MELBOURNE, Australia (AP) — The Latest on the Australian Open (all times local):

3:05 p.m.

Serena Williams has been pushed to a third set by No. 7 seed Aryna Sabalenka at the Australian Open with a quarterfinal berth on the line.

Williams took the opening set 6-4, but Sabalenka broke serve three times in a row in the second to grab it by a 6-2 score.

Williams is trying to get closer to her 24th Grand Slam singles title and eighth at Melbourne Park.

Sabalenka has never made it past the fourth round at a major tournament.

The winner will face either Simona Halep or Iga Swiatek.

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1:10 p.m.

Naomi Osaka fought off two match points and came back to eliminate Garbiñe Muguruza in a big-hitting fourth-round matchup of Grand Slam champions at the Australian Open.

The third-seeded Osaka grabbed the last four games to win 4-6, 6-4, 7-5 in Rod Laver Arena.

That result puts her back in the quarterfinals of a tournament she won in 2019 for one of her three major trophies.

Osaka was serving at 15-40 while trailing 5-3 in the final set. But Muguruza could not convert either of those match points and wouldn’t win another game.

Osaka now faces unseeded 35-year-old Hsie Su-wei of Taiwain with a semifinal berth at stake.

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12:25 p.m.

Unseeded Hsieh Su-wei has reached her first career Grand Slam quarterfinal at age 35.

Hsieh's 6-4, 6-2 victory over 2019 French Open finalist Marketa Vondrousova made her the oldest woman to make her major quarterfinal debut in the professional era.

This is Hsieh's 38th main-draw appearance at a major tournament.

The 19th-seeded Vondrousova made 31 unforced errors, 13 more than Hsieh.

Hsieh is ranked 71st and plays with an unusual style that includes two-handed shots off both sides.

She beat 2019 U.S. Open champion Bianca Andreescu in the second round at Melbourne Park.

Next up for Hsieh will be the winner of the fourth-round match between Naomi Osaka and Garbiñe Muguruza.

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11 a.m.

Novak Djokovic — if he is healthy enough to play — and Serena Williams headline Day 7 as the fourth round of the Australian Open gets started.

There will not be any spectators in the stands because of a five-day lockdown imposed by the government in reaction to new COVID-19 cases in the area.

The first quarterfinal berths will be at stake with four women's matches and four men's matches on the singles schedule Sunday (Saturday EST).

Williams continues her quest for a record-tying 24th Grand Slam singles title when she plays No. 7 seed Aryna Sabalenka in the second match at Rod Laver Arena.

That will follow the matchup between three-time major champion Naomi Osaka and two-time Slam trophy winner Garbiñe Muguruza.

Two other Grand Slam champions, Simona Halep and Iga Swiatek, will open the night session in Laver.

Their match is to be followed by eight-time Australian Open champion Djokovic against 2016 Wimbledon finalist Milos Raonic — assuming Djokovic decides he can play.

The No. 1-ranked Serb hurt a stomach muscle when he fell during his fourth-round victory over Taylor Fritz and skipped practice on Saturday.

Other men in action include reigning U.S. Open champion Dominic Thiem and the man he beat in that final, Alexander Zverev.

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