World No. 2 Swiatek has won six Grand Slam titles but lacks an Australian Open title.
Elena Rybakina initially struggled with her serve in the first set, but recovered and outplayed Swiatek, winning the set 2–0.
"I'm really happy with the win. I think in the second set I just started playing more freely and serving better," the 26-year-old said, according to AP.
Rybakina, from Kazakhstan and ranked fifth in the world, has now advanced to the semifinals of the tournament and will face American Jessica Pegula on Thursday.
