A day after her 35th birthday, Azarenka ousted 73rd-ranked Wang Yafan 6-1, 6-7 (5/7), 6-3 after two hours and 46 minutes to advance at the US Open hardcourt tuneup.
Top seed Sabalenka, the 2023 and 2024 Australian Open winner, and her sixth-seeded Belarus compatriot are the only two seeds in the last eight ahead of Friday's showdown.
"The most important thing right now is playing an opponent like Aryna and seeing where my game is at and what I can do," Azarenka said. "My focus is more internal this week for the purposes of preparing for the US Open."
World number three Sabalenka owns a 4-1 edge in her WTA career rivalry with 20th-ranked Azarenka after taking their most recent matchup in January in a Brisbane semi-final.
"I had a lot of great matches against Victoria. It's always great matches against her," Sabalenka said. "I'm really looking forward facing her again."
Sabalenka won their first meeting in the opening round at the 2019 US Open while Azarenka took a 2020 US Open second-round rematch. The other Sabalenka triumphs included the 2020 Ostrava final and a 2021 Montreal quarter-final.
"Maybe from our last matches I can try some new things to hopefully turn it my way," Azarenka said.
Both Sabalenka and Azarenka withdrew from Wimbledon with shoulder injuries but haven't had problems this week.
"I was able to serve without pain," Sabalenka said. "It's not going to be easy to come back after injury, especially the one I had. I feel OK."
Azarenka, who won the 2012 and 2013 Australian Opens, was confident matches would restore top form.
"Not having a lot of matches under the belt lately and also coming off injury, I think the positives are that I played almost three hours in back-to-back matches and my shoulder feels good," Azarenka said.
"That was one of my main goals this week, that I'm able to handle the match play."
Rublev to face Tiafoe
On the men's side, top seed Andrey Rublev reached the quarter-finals by defeating French 16th seed Arthur Rinderknech 7-6 (7/4), 6-4.
Rublev and Rinderknech held serve into a first-set tie-breaker, where the Russian took three of the last four points, including his 14th ace, and took the first set after 49 minutes when the Frenchman netted a forehand.
In the second set, Rinderknech swatted a backhand long to surrender a break in the ninth game and Rublev finished off the match after 88 minutes with his 19th ace.
Rublev will next face US fifth seed and hometown hero Frances Tiafoe, who outlasted American Aleksandar Kovacevic 7-6 (7/3), 4-6, 6-3.
US second seed Ben Shelton edged countryman Brandon Nakashima 7-6 (7/5), 7-6 (7/4) to reach a Friday quarter-final against Canadian wildcard Denis Shapovalov, who ousted Serbian Miomir Kecmanovic 4-6, 6-4, 6-2.
