The hometown favorite required just an hour and 18 minutes to dispose of Kazakhstan's Elena Rybakina, 6-3 6-2.
Rod Laver Arena was packed to capacity as the home crowd cheered and supported their local hero.
Brandishing a game tailored to disrupt any opponent's rhythm, Barty employed big serves with powerful groundstrokes and heavy slices. The 26th-ranked Rybakina was completely overwhelmed in the first set, as Barty took that in just over 30 minutes.
Rybakina attempted a comeback in the second set, but was unable to capitalize on her numerous break point opportunities. Trailing 1-3, a second break of serve sealed her fate as the defending Roland Garros champion ran away with the victory.
Being a clear favorite to lift the title, Barty has been impressive the entire tournament. Coming off a victory in Adelaide a week ago, the Australian has been in superb form and looks to continue her unbeaten streak.
Barty next faces the winner between doubles partner Julia Goerges and American Alison Riske.
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