The defending champion was knocked out of the competition by Agnieszka Radwanska in a 6-1 5-7 6-0 defeat at the Rod Laver Arena on Wednesday, in a game littered by unforced errors by the world number two.
"I just didn't have the focus on finishing the point. She really took advantage of that," Azarenka told reporters.
"My game wasn't there as I wanted it. She was aggressive, she was making everything."
Radwanska will play 20th seed Dominika Cibulkova for a place in the final.