New Western Sydney import Sarina Bolden has ended a personal goal drought to help the Wanderers send A-League Women ladder leaders Western United to their first defeat.
The 2-1 loss was United's first after seven straight wins, while Western Sydney posted their second successive major upset following their defeat of Melbourne City.
The Wanderers' 53rd-minute winner came from a rare indirect free kick in the penalty area, awarded after a backpass.
The ball on the left edge of the six-yard box was played to Amy Harrison who lashed her shot past the wall and into the net.
"When she (the referee) said indirect free kick I had to remind myself that the ball had to be touched," Harrison told AAP.
"When you are that close to goal you go for it and I did that and it paid off."
United almost salvaged a point at Wanderers Football Park, hitting the post near the end as they fought to preserve their unbeaten record.
The home side, though, secured back-to-back wins for the first time since February 2021.
Sophie Harding and Bolden consistently caused problems for the United defence and they combined for the opener in the 12th minute.
Philippines international Bolden scored her first ALW goal in her second game from Harding's pass.
"In the Japanese league I hadn't scored, I'd only gotten one assist for about a season and a half," Bolden said.
Bolden and Harding both had good chances to double the lead before the visitors equalised on 26 minutes.
Hannah Keane scored her third goal in four days with a fine far-post header from a Khali Johnson cross.
It was United's only first-half effort on target and the American's sixth goal of a productive campaign.
Buoyed by the equaliser, the league leaders became more assertive and dangerous as the half progressed.
Danielle Steer struck a post from the edge of the area in the 45th minute and shortly after Julia Sando floated a shot just over the bar.
United brought new signing Angie Beard and Matildas stalwart Chloe Logarzo off the bench just before the hour.
"I think we can still be proud of them way we played and the way we grinded right to the end," Steer said.
Asked about the awarding of the indirect free kick for the backpass Steer, added: "I think there was a fair lot of confusion with that."