MELBOURNE, Australia — Once again, Serena Williams came within reach of a record-tying 24th Grand Slam singles title, playing well enough to get to the closing days of a major tournament.

And once again, Williams couldn't quite get it done — beaten 6-3, 6-4 by Naomi Osaka in the Australian Open semifinals on Thursday (Wednesday night EST).

Osaka, who also beat Williams in the chaotic 2018 US Open final, reached her fourth major title match and stretched her winning streak to 20 matches by claiming the last eight points.

"I don't know if there's any little kids out here today, but I was a little kid watching her play," Osaka, 23, said about Williams, 39, "and just to be on the court playing against her, for me, is a dream." The No. 3-seeded Osaka's Grand Slam collection also includes last year's US Open and the 2019 Australian Open and she is, without a doubt, the most dangerous hard-court player in the women's game at the moment.

That used to be Williams, of course. But she was off-target too much in this contest, finishing with twice as many unforced errors, 24, as winners, 12.

After collecting her professional era-record 23rd major singles trophy at the Melbourne Park in 2017 while pregnant, Williams has not been able to pull even with Margaret Court's mark of 24 for the most Grand Slam titles in history.

Since returning to the tour in 2018 after having her daughter, Williams has reached four major finals and lost them all. She's also now lost in the semifinals twice in that span.

On Saturday, at 7:30 pm. local time (3:30 am. EST), Osaka will meet a first-time Grand Slam finalist for the championship. No. 22 Jennifer Brady of the United States was scheduled to face No. 25 Karolina Muchova in Thursday's second semifinal.

One men's semifinal was on Thursday's schedule: No. 1 Novak Djokovic vs. Aslan Karatsev, a qualifier from Russia who is ranked 114th and playing in his first Grand Slam tournament.

Djokovic is seeking a ninth Australian Open title and 18th Grand Slam trophy overall. Rafael Nadal — who lost in the quarterfinals to Stefanos Tsitsipas after blowing a two-set lead — and Roger Federer are tied for the men's record of 20.

Spectators were back in the stands at Rod Laver Arena on Thursday after they were barred from attending the tournament for five days during a local COVID-19 lockdown. About 7,000 people were allowed into the stadium for Williams-Osaka, roughly half of capacity.

Ushers walked through the aisles at changeovers to remind fans they needed to wear a mask or over their nose and mouth.

On the hottest day of the hard-court tournament so far — 85 degrees Fahrenheit (30 Celsius) — Osaka got out to a shaky start, perhaps prodded into pressing in her opening service game by a booming cross-court backhand return winner from Williams on the match's second point. That was followed by a double-fault, a wild forehand and, eventually, a netted backhand that handed over a break. Quickly, Williams went up 2-0, then held another break point with a chance to lead 3-0 after another double-fault by Osaka.

"I was just really, like, nervous and scared, I think, at the beginning," said Osaka, who was born in Japan and moved to the U.S. when she was 3. "And then I sort of eased my way into it." Didn't take long to right herself, however.

Suddenly, it was Osaka powering in aces, putting groundstrokes right where she wanted, covering the court so well. Williams' movement has been terrific in Melbourne, but she suddenly was flat-footed, her miscues accumulating precipitously. Five games went by in a flash, all into Osaka's column, and soon enough, the first set belonged to her, too.

Williams' frustration was made plain early in the second set, when she leaned over at the baseline and screamed, "Make a shot! Make a shot!" Osaka never has tried to hide how much she admires Williams and models her game after the American's. Both are predicated on the same basic elements of big serves and quick-strike forehands, and not only did Osaka do both better on this day, she even sounded just like her idol, screaming "Come on!" after several key shots.

Williams herself began to get louder and increasingly animated the deeper into the second set they went — and plenty of folks on hand were excited to show their support, clapping and yelling after each successful stroke.

Those pulling for Williams got their wish: Osaka blinked. A trio of double-faults in one game — she wound up with eight for the match — allowed Williams to break for 4-all.

But Osaka regained her composure immediately, breaking back at love with the help of a pair of backhand winners and a double-fault from Williams, then holding at love to end it.