Sabalenka needed just over an hour to dismantle Russian prodigy Mirra Andreeva 6-1 6-2 at Rod Laver Arena on Sunday.
She will next face Anastasia Pavlyuchenkova - a rare player with a winning record against her, after the Russian beat injured Croatian 18th seed Donna Vekic 7-6 (7-0) 6-0.
Third seed Coco Gauff survived a massive scare from Belinda Bencic, winning 5-7 6-2 6-1 to tee up a quarter-final with 11th seed Paula Badosa, who reached the final eight for the first time.
Coco Gauff rallied to defeat Switzerland's Belinda Bencic. (James Ross/AAP PHOTOS)
Badosa beat unseeded Serb Olga Danilovic 6-1 7-6 (7-2) on Margaret Court Arena.
Sabalenka, 26, became the youngest player to win 18 consecutive grand slam matches on hard court since legend Williams from 2002 to 2004, having also claimed last year's US Open title.
Andreeva, 17, was supposed to be the back-to-back champion's first big test this campaign but the 14th seed proved mere cannon fodder as the powerful top seed blasted her off the court.
Hard-court specialist Sabalenka, who also won the Brisbane International, could become the first player since Martina Hingis between 1997-1999 to win three Opens on the spin.
"Of course, there's the pressure. It doesn't matter if you are No.1, No.2 or No.10. There is always the pressure," Sabalenka said.
"It's all about focusing on yourself, having fun outside of the court, take it easy outside of the court, because there is enough pressure on the court.Â
"It's all about the balance."
Andreeva looked shellshocked as Sabalenka raced away to claim the first set in just 24 minutes.
Power � finesse � Sabalenka— #AusOpen (@AustralianOpen) @wwos • @espn • @eurosport • @wowowtennis • @SabalenkaA • #AO2025 pic.twitter.com/x5evl2UL6gJanuary 19, 2025
While Sabalenka had some testing moments on serve in the second set, she never lost control, wrapping it up in 38 minutes.
Bencic, the Tokyo Olympics singles gold medallist went toe-to-toe with Gauff from the baseline as she claimed the first set.
But Gauff hit back in the second set, then ran away with it in the decider.
"In the first set she played great tennis and it was tough for me to be on the offence," Gauff said.
"I just played more aggressively in the second set and also the third set."
Gauff's next opponent Badosa eased through her first set against Danilovic then fought back from 5-2 down to take the second to a tiebreak, which she easily won.
Paula Badosa blows a kiss after advancing to the quarter-finals. (Lukas Coch/AAP PHOTOS)
"I entered the court honestly super nervous today because sometimes as a tennis player you see opportunities," Badosa said.
"I think today was a day like that and I tried to focus as much as I can to play my game, be aggressive."
Pavlyuchenkova fought to claim a first-set tiebreak against Vekic, then ran away with the match in the second set as the Croatian dealt with a knee injury.
Anastasia Pavlyuchenkova belts a forehand in her win over Donna Vekic. (Joel Carrett/AAP PHOTOS)
In her 20th year on the tour, the 33-year-old Pavlyuchenkova then wrote on the camera lens: "Too old but still here! Ooops!"
The 27th seed has a 2-1 record against Sabalenka, most recently beating her at the 2021 French Open.
"She hits the ball so well, so powerful and not many girls are able to do that," Pavlyuchenkova said.
"But I also hit the ball hard, so let's see."
