Top-ranked Ash Barty was upset in the Australian Open quarterfinals by 25th seed Karolina Muchova of the Czech Republic.
Muchova prevailed 1-6, 6-3, 6-2 over the Australian to reach her first Grand Slam semifinal.
She gets the winner of a later all-American quarterfinal between No. 22 Jennifer Brady and 61st-ranked Jessica Pegula, the daughter of Buffalo Bills and Buffalo Sabres owners.
Barty’s defeat means that the winner of Thursday’s semifinal between Naomi Osaka and Serena Williams will likely be a significant favorite to win the tournament.