MELBOURNE, Australia — So good for so long lately, Naomi Osaka was just one point from the end of her lengthy winning streak, one point from leaving the Australian Open with a loss to Garbine Muguruza.
Bleak as things looked for her late in a big-hitting matchup of Grand Slam champions and former No. 1-ranked women, Osaka never wavered, erasing two match points and grabbing the last four games to edge Muguruza 4-6, 6-4, 7-5 at Rod Laver Arena in the fourth round Sunday.
The third-seeded Osaka returns to the quarterfinals of a tournament she won in 2019 for one of her three major trophies. Osaka ran her winning streak to 18 matches — a run that included a US Open title in September — and put a stop to Muguruza’s own fine form of late.
Heading into Sunday — the second day of the tournament without any spectators, because of a local COVID-19 lockdown — two-time major champion Muguruza had been broken only once in this Australian Open. She had dropped a total of 10 games through three matches.
But Osaka broke her five times and won 17 games in all in a contest featuring entertaining baseline back-and-forth play and terrific serving by both on a cloudy day with the temperature in the mid-60s.
“I was a bit intimidated, because I knew that she was playing really well coming into this match,” Osaka said. “In the stressful points, I feel like I just had to go within myself. And I know that today I probably hit a lot of unforced errors, but I feel like it was what I needed to do, because I couldn’t really give her any short balls because she would finish it.”
Osaka wound up with more unforced errors, 36-28, but also more winners, 40-24.
The key moment came when Osaka was serving at 15-40 while trailing 5-3 in the final set. Muguruza could not convert either of those match points: Osaka delivered one of her 11 aces at 118 mph on the first; Muguruza missed a groundstroke on the second.
Fifteen minutes later, the match would be over.
Muguruza served for the win in the next game and got broken when Osaka smacked a cross-court forehand winner to close a 14-stroke exchange. After holding to go up 6-5, Osaka broke Muguruza yet again to win their first head-to-head meeting.
Osaka, a 23-year-old who was born in Japan and moved to the U.S. with her family when she was 3, now faces unseeded 35-year-old Su-Wei Hsieh of Taiwan with a semifinal berth at stake.
“I’m not really looking forward to it,” Osaka said. “She’s going to be really tough.”
The other fourth-round matches on this side of the women’s draw were later Sunday: Serena Williams vs. Aryna Sabalenka, and Simona Halep vs. Iga Swiatek.
The 71st-ranked 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 Grand Slam tournament.
Hsieh plays with an unusual style that includes two-handed shots off both sides, and that might have flustered the 19th-seeded Vondrousova, who made 31 unforced errors, 13 more than the winner.
Hsieh beat 2019 US Open champion Bianca Andreescu in the second round.