Serena Williams takes final bow at 2022 US Open after third-round defeat to Ajla Tomljanovic

WATCH: Serena scored a three-set stunner over No. 2 seed Anett Kontaveit just to reach the third round at the US Open.

NEW YORK—Serena Williams took what is very likely the final step in her evolution away from tennis on Friday night, enduring a 7-5, 6-7 (4), 6-1 defeat to Ajla Tomljanovic at the US Open.

"She's Serena," Tomljanovic said on court. "That's just who she is, and she's the greatest of all time. Period."

The 23-time Grand Slam champion previously revealed that the Open would likely be her final major tournament in a Vogue editorial published last month, and though she showed flashes of her vintage brilliance through three matches, she ultimately came up just short against the Aussie after three hours, four minutes, and six match points in front of an emotional Arthur Ashe Stadium crowd.

After a solid summer that included a second straight Wimbledon quarterfinal, Tomljanovic was understandably eager to take on Williams for the first time, speaking about it after her second-round win over Evgeniya Rodina on Wednesday.

“It's going to be a huge moment no matter the outcome,” she said.

“No matter the fact that I've been a Serena fan since I was a kid, on Friday night I'll just be a competitor and I'll try my best to win.”

For her part, Williams has been in the midst of morphing from sentimental favorite to legitimate title contender over her last two matches, edging through a nervous opener against Danka Kovinic to play some of her best tennis in two years to stun No. 2 seed Anett Kontaveit.

It's been a fun ride. It's been the most incredible ride and journey I've ever been on, I mean, in my life. I'm just so grateful to every single person that's ever said, Go, Serena, in their life. I'm just so grateful. Yeah, I mean, you got me here. Serena Williams

“I feel like I've already won, figuratively, mentally,” she insisted after the three-set win over Kontaveit. “It's just pretty awesome the things that I've done.

“I never, like, accept that. I never think about it, so tonight I was just like, ‘Serena, you've already won, just play, be Serena.’”

She was very much Serena to start her third night session clash with the Aussie, putting down a break at love to find herself serving for the opening set.

Tomljanovic took over from there, balancing an even nine winners to nine unforced errors as she secured four straight games from 5-3 down.

With a full Ashe Stadium crowd on edge, Serena wrested momentum back in some style, winning the first four games of the second set and putting the contest on a seemingly inevitable course for a decider.

But pressure continued to mount on the former world No. 1 as Tomljanovic slowly worked her way back into proceedings, clawing one break back and saving four set points on her own serve to again even the set at five games apiece, Serena double-faulting on break point.

On the brink of what would be a career-ending defeat, Serena found her vintage best in the ensuing tiebreaker—converting fifth set point and kicking off the final set with a fourth service break.

Once again, Tomljanovic hit another hot streak, winning five straight games just as Williams verged on a 2-0 lead, this time to put herself within four points of her first US Open second week.

Serena made a brave last stand as only Serena can, saving five match points with some of her best winners of the night. Tomljanovic gamely three a pair of break points in a marathon seventh game—even as Serena continued to play some incredible tennis. She earned a sixth match point with an ace, and with a forehand into the net from Serena, it was all over.

Serena's 27-year career ends with an Open Era-record breaking 23 Grand Slams, 319 weeks at No. 1.

In what she assures fans are "happy tears" during the on-court interview, Serena thanked parents Oracene Price and Richard Williams, husband Alexis, daughter Olympia, and elder sister Venus, with whom she played one last doubles match on Thursday.

"She's the only reason Serena Williams ever existed."

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