MELBOURNE, Australia >> Within an hour of her third-round loss at the Australian Open, defending champion Naomi Osaka had consigned it to the past.

It’s part of her new resolution for 2022. No dwelling on what’s already happened.

Osaka had two match points against 60th-ranked Amanda Anisimova in the third set Friday, and she missed two backhands.

Anisimova held serve to force a tiebreaker, which she dominated, and finished with an ace for a 4-6, 6-3, 7-6 (5) comeback victory over the four-time major champion.

In doing so, the 20-year-old American ensured that the so-called final-before-the-final — a much-anticipated fourth-round showdown between Osaka and top-ranked Ash Barty — won’t happen.

“I’m not sure if I’m going to have regrets about those two match points,” Osaka said. “Like, I thought she played really well. But I can’t really look in the past anymore, you know?

“Like I just have to focus on what I can do in the future to hopefully evade those situations.”

Anisimova, who had lost her previous nine matches against top 20 players and had to rebound from a set and a break down to survive her first-round match, hit 46 winners to Osaka’s 21.

Osaka, one of the most powerful hitters in the women’s draw, praised Anisimova’s service returns and described how the ball kept coming back at her so low and fast that she couldn’t adjust her footwork to counter it.

“I just want to soak in this moment,” said Anisimova, who took out Olympic champion Belinda Bencic in the second round. “It was an amazing match. It was very close. You know, there were a bit of nerves, and to play Naomi for the first time … it’s unreal, honestly.”

Anisimova won her first WTA hardcourt title at a tuneup tournament in Melbourne this month and is now on an eight-match winning streak — the longest of her career in main draw matches.

It’s the fourth time Osaka has been unable to defend a major title, and the 11th time in her 21 trips to Grand Slam events she has been knocked out in the third round, including last year’s U.S. Open.

After winning the title last year — her second at Melbourne Park in three years — Osaka withdrew from the French Open in the second round and skipped Wimbledon to take a break for her mental health. After her tearful exit at the U.S. Open, she took an extended layoff to reset and arrived at the year’s first major with a seeding of No. 13. She also brought a new approach, vowing to enjoy the game more and never again cry in a news conference. She’s spent time meditating, keeping a journal of things she needs to be grateful for, and more time hanging out with family and friends.

“I can’t win every match. So I just have to, like, take that into account,” Osaka said. “I feel like I grew a lot in this match. The last match that I played in New York I think I had a completely different attitude, so I’m really happy with — you know, of course I lost, but I’m happy with how it went.”

Barty is hoping to become the first Australian woman to win the championship here since 1978.

She advanced to the fourth round with a 6-2, 6-3 win over 30th-seeded Camila Giorgi and has only conceded eight games and spent less than three hours on court.

A career break a few years back, to play professional cricket, did Barty a world of good. Since her return, she won her first Grand Slam title at the 2019 French Open — beating Anisimova in the semifinals — and won Wimbledon last year.

The hype surrounding the fourth round didn’t impact her planning.

“Each match is uncertain. You just have to navigate your way through as best you can that given moment,” Barty said. “I’ve done a good job of that this week. Now it’s exciting to get to play Amanda again.”

Osaka’s loss means Victoria Azarenka remains the last woman to successfully defend an Australian Open singles title. She overpowered 15th-seeded Elina Svitolina 6-0, 6-2 to reach the fourth round at Melbourne Park for the first time since 2016.

She had her son with her at a news conference and five-year-old Leo, wearing his sunglasses and sitting on his mother’s knee, described the two-time champion’s form as: “Awesome!”

The 2012 and 2013 titlist will next play French Open champion Barbora Krejcikova, who rallied from a set and a break down to beat 26th-seeded Jelena Ostapenko 2-6, 6-4, 6-4.

Since a quarterfinal run in Australia in 2016, Azarenka lost first-round matches last year and in 2019, and missed the hard-court tournament in 2017, 2018 and 2020.

Other fourth-round pairings that were set up Friday include fifth-seeded Maria Sakkari against 21st-seeded Jessica Pegula and No. 8 Paula Badosa against Madison Keys, who held off Wang Qiang 4-6, 6-3, 7-6 (2) on Friday.

Rafael Nadal wrapped up the Day 5 program on Rod Laver Arena by beating Olympic silver medalist Karen Khachanov 6-3, 6-2, 3-6, 6-1 and continuing his bid for a men’s record 21st Grand Slam title.

Olympic gold medalist Alexander Zverev had a 6-3, 6-4, 6-4 win earlier over Radu Albot, a 124th-ranked qualifier from Moldova. The third-seeded Zverev will next play No. 14 Denis Shapovalov, who beat Reilly Opelka 7-6 (4), 4-6, 6-3, 6-4.

Wimbledon runner-up Matteo Berrettini fended off 18-year-old Spaniard Carlos Alcaraz 6-2, 7-6 (3), 4-6, 2-6, 7-6 (5).

Miomir Kecmanovic continued to make the most of the absence of fellow Serbian Novak Djokovic, reaching the fourth round at a major for the first time with a 6-4, 6-7 (8), 6-2, 7-5 win over 25th-seeded Lorenzo Sonego.

He will next play 17th-seeded Gael Monfils, who beat No. 16 Cristian Garin 7-6 (4), 6-1, 6-3.

Kecmanovic had been drawn to play the top-ranked Djokovic, a nine-time Australian Open champion, in the first round. But Djokovic was deported on the eve of the tournament for failing to meet Australia’s strict COVID-19 regulations.