World number one Iga Swiatek was left in tears after a straight-set defeat by American Jessica Pegula in the semi-finals of the inaugural United Cup.
Pegula, ranked third in the world, needed just 71 minutes to wrap up a dominant 6-2 6-2 win in Sydney.
Poland's Swiatek, the French and US Open champion, had beaten Pegula in their previous four meetings.
"She's one of the best players in the world so you have to be really on top of your game to win," Swiatek said.
"It was always like that, even last season, so I'm not surprised, because I know what she can do.