Having blitzed a pair of qualifiers in her first two matches, Barty made equally light work of world No.33 Camila Giorgi in a 6-2 6-3 victory on Friday night.

The result extended the world No.1's unbeaten run in 2022 to seven matches as the local favourite closes in on a third career grand slam title and first on home soil.

Forecast to face Osaka in a fourth-round blockbuster, Barty will instead meet Anisimova after the American world No.60 fought off two match points to upset the two-time champion 4-6 6-3 7-6 (10-5) in the shock of the Open so far.

Anisimova and Barty last clashed in an epic semi-final at the French Open in 2019, when Barty blew a 5-0 lead in the first set and trailed 3-0 in the second.

She recovered to win through to the final and claimed her first major title on the Paris clay.

The 25-year-old now regards that semi-final as the major turning point in her glittering career.

"It feels like it's a lifetime ago but some of those memories are still really vivid," Barty said.

"Without a doubt we''ll take that experience and use those feelings and emotions as best we can come Sunday."

Free-hitting Giorgi never seriously challenged Barty, who is now unbeaten in four career encounters with the Italian.

Barty again banked on her biggest weapon - her clinical serve - and is yet to be broken in 23 service games at Melbourne Park this year.

She held her nerve to save all four break points against Giorgi and has won 84 per cent of points after landing her first delivery.

Barty has won 57 consecutive service games stretching back to her first match of the year at the Adelaide International against Coco Gauff.

"(My serve) has been really solid over the last couple of weeks," Barty said.

"Particularly in Adelaide, I felt like I found a really good rhythm with it and here so far in my matches I've been able to squeeze out of a few really tough games.

"The one tonight from love-40 into the wind was a big game and I felt like, once I was able to steady the ship with that one, I got a little bit more confidence just to go up and hit my spots and still be aggressive.

"All in all, it's been a really positive start with regards to the serving."

Barty will need more of the same to overcome Anisimova, who recovered from a set down to topple Osaka and turn the Open upside down.

Anisimova also ousted Tokyo Olympics gold medallist Belinda Bencic on her unlikely way to the fourth round.

"Going into this match, I knew I had to be playing sharp if I wanted to give myself a chance," Anisimova said.

"Naomi is always going to be playing well - she's an absolute champion.

"I knew I had to step up my game and try to be aggressive and I think that's what I started doing in the second set.

"I'm so grateful that I was able to play so well and get this win, it means a lot.

"I'm just having fun and getting the win on this day is just a huge bonus, and I'm looking forward to my next round."

Australian Associated Press