Barty will next play American Danielle Collins, who beat No. 7-ranked Belinda Bencic 6-3, 6-1.
Barty lost her first match at the Brisbane International last week but has showed steady improvement in Adelaide.
“That is just a gradual progression of spending time on court and spending time in that competition mode,” Barty said.
Aryna Sabalenka will meet Dayana Yastremska in the other semifinal on Friday.
Yastremska beat Donna Vekic 6-4, 6-3, while Sabalenka defeated second-seeded Simona Halep 6-4, 6-2.
Halep won the 2018 French Open and 2019 Wimbledon. She reached the Australian Open final in 2018.
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