Well, I don't know what to do with myself after that.

Such a spectacular match ending with the "upset" win, but really fitting. So glad that Serena went out on her shield in an epic contest, and it was an Aussie that played the match of her life to do it.

Williams left the door open for a return, but even if that does happen some time, I think this is the last we're going to see of her for a good long while.

We'll have A LOT of coverage of the US Open and a wider look back as Serena's career over on ABC Sport, so keep that page bookmarked for all the latest.

See you next time, and thanks for hanging around.

Genuinely one of the best US Open matches I've ever seen.

This is now her outright best US Open performance (she's never passed the third round before) but how far can she carry it.

Next up is a match with world number 35 Liudmila Samsonova, but a lot of dangerous players — former champions and finalists like Naomi Osaka, Sloane Stephens, Leylah Fernandez and Emma Raducanu, plus the second, third and fourth seeds — have been knocked out.

And if Tomljanović can win this match, literally anything is on the cards.

Ajla Tomljanović has been to the quarter-finals of Wimbledon for the past two years, but she doesn't have any single titles to her name.

Considering the opponent, the stage and the quality of the match, I think you'd have to say this is the biggest victory of the 29-year-old's career.

In every set and in seemingly every game she fought back. I lost count of the number of times in that match that less resilient players would have chucked in the towel. Honestly, I think that's something Williams has relied on late in her career — opponents being overwhelmed and overawed by the moment, the power, the Serena of it all — but Tomljanović just kept coming at the great champion.

Williams had more aces, more winners and fewer double faults, but Tomljanović was objectively the better player on the day.

Tomljanović apologises for ending Williams's career (for now).

"I'm feeling really sorry. What she's done for me for the sport is just incredible.

"This is a surreal moment for me."

She's asked how she handled the pressure, and it was simple for the Australian.

"I just thought she would beat me. The pressure wasn't on me.

"She's Serena. She's the greatest of all time. Period."

She was clearly close to tears as she waved to the crowd. I don't even know if Ajla Tomljanović had the chance to do so.

Williams gets the first on-court interview.

"I tried but Ajla just played a little bit better.

"Thank you daddy, I know you're watching. Thanks mum. ... I'm really grateful for them.

"And I wouldn't be Serena if there wasn't Venus, so thank you Venus. She's the only reason Serena Williams ever existed.

"Everyone that's here, who's been on my side for so many years.

"It's been a fun ride and the most incredible journey I've ever been on."

A glimmer of hope for a comeback?

"I don't think so, but you never know."

First point in the bag as Williams sprays a backhand return wide. 15-0

Williams fights back with a forehand return winner and the crowd erupts again like Rocky just got up off the canvas. 15-15

Tomljanović sends a forehand long, and Williams has a sniff at 15-30.

Just sensational from Tomljanović, after flattening out so many forehands, she rips over the top of one to get the cross-court angle for a winner. 30-30

And then forces the forehand error from Williams. MATCH POINT!

Williams saves the first, storming the net and finishing with a backhand winner. Deuce

The umpire has to step in and tell the crowd to hush as Tomljanović serves a fault, but Williams can't capitalise on the second serve, and that's another match point for Tomljanović.

Williams is going for everything on these groundstrokes and painting the lines. Tomljanović will have to win this off her own racquet. Deuce

BANG! Huge forehand winner from Tomljanović. A third match point for the steely Aussie.

OH GET LOST! That forehand winner off the return!? Now?!?! How though? It was so shallow and angled I thought it might have been framed, but nope. Back to deuce.

Ajla Tomljanović! Every great Williams return seems to be coming back with interest, and it's given her a fourth match point.

Williams saves another one! Pure aggression. So brave when facing match point. And hitting targets too. Deuce

Tomljanović misses a short forehand long! And Williams has a break point.

Save by Tomljanović with a major second serve and a beastly forehand. Speaking of brave play. Deuce number five as we tick over three hours.

Match point number five for Tomljanović as Serena miscues a return. but it's saved by Williams again as she pounces on a second serve with a forehand winner. Deuce

Tomljanović completely miscues one, almost hitting her forehand under the net. Advantage Williams again.

But this break point goes begging too, as Tomljanović's groundstrokes keep rushing Williams, who frames one long. Deuce

Net cords galore, drop shots and some tired shot making from Tomljanović, but Williams wins the point with an overhead backhand volley. She gets another break point. I'm tired.

OH MY GOD!!!She's going for every shot in her arsenal and it earns her another match point.

AND SHE GETS IT THIS TIME!!!! Ajla Tomljanović wins!

She makes it 30-0, but not without a massive fight from the Aussie, who once again is all over the baseline.

Tomljanović comes up with a perfect forehand cross-court winner. 30-15

She works her way back into it at 30-0, and now she's the one dictating from the baseline with her returns.

Break point as she flattens out everything, really rushing Serena. 30-40

She gets the break!

And she races to 40-0. Williams looks knackered, and Tomljanović knows it.

Double fault. She has some points to play with, but Williams can flip this again with two returns. 40-15

And there's one. Unbelievable depth, right at the toes of Tomljanović as she finished her service motion. 40-30

Oh, so close! Another perfect backhand return from Williams, but Tomljanović digs it out and forces the GOAT to paint the lines, but she can't do it.

Game Tomljanović.

She gets to 15-0 in a hurry, but gives it back with a miscued drop shot. 15-15

Tomljanović's attempt looked better, but just couldn't sneak over the net cord. 30-15

Sensational backhand down the line from Tomljanović to pass Williams at the net. 30-30

Double fault. Break point chance for Tomljanović. 30-40

Ace out wide. What a save. Deuce

Williams has got to be rubbing up against a time violation with her pace between points right now. But I certainly would be wary calling her for one at this point in the match. On this court.

Superb groundstrokes from Tomljanović gives her another break point, but again Williams saves herself with a big serve down the T.

Double fault. Another break point for Tomljanović. But my lord what a point to save it, from both players. Tomljanović all over the baseline, Williams north and south from the back to the net and back again, eventually winning it with a tough drive volley. Deuce again

Tomljanović bunts the return back in, forcing Williams to generate the pace, and her backhand is net-bound. Another break point.

Tomljanović gets the break! Williams went for an overhead drive volley instead of a traditional volley or smash after Tomljanović wrong-footed her, and that's the break for this unflappable Australian.