Sabalenka has enjoyed a quiet run in Melbourne so far and has also seen some of her title rivals exit early.
Seatek's first two matches kept the world number one on the court for more than five hours, as the Polish player was forced to come back from the brink against Danielle Collins in the second round.
Third seed Elena Rybakina, who Sabalenka beat in last year's final, lost in a record second-round tiebreak, while fifth seed Jessica Pegula also lost on Thursday.
By contrast, Sabalenka has spent just under three hours on court and has yet to be physically tested.
She reached the semi-finals at all four Grand Slams last year but says she is in better form this year, saying in her on-court interview that “Arina 2024” will beat Sabalenka last season.
“I think the performance today was perfect,” she said. “There's always something to improve, you know.
“You can't be happy with the level you're at now, so you always have to keep moving and keep improving.”
She may face a more difficult test against Anisimova, who is playing her first major tournament since taking a seven-month break due to her mental health, and beat former world number two Paula Badosa 7-5, 6-4.
Sabalenka will likely face Gauff, who she beat in the New York final last year, in the semifinals.
Gauff has not dropped a set so far in this year's tournament and was equally dominant against fellow American Parks on Friday.
She will face Polish Magdalena Fritsche, who defeated Russian qualifier Anastasia Zakharova in three sets, while Sabalenka will play Amanda Anisimova.
