Senior midfield reserve Ena Sabanagic's goal 58 seconds before halftime was the difference as Purdue posted a stunning 1-0 victory for its first tournament win since 2008.
The Badgers (14-3-2) outshot the Boilermakers (8-8-3) by a wide margin in each half, finishing with a 7-3 shots on goal advantage and 16-5 overall advantage, but couldn't get anything past sophomore goalie Marisa Boya, who made six saves.
Ranked seventh in the nation, UW will find out its next opponent on Nov 11 when the NCAA tournament selection show is held at 3:30 p.m.
In other tournament quarterfinal matches, second-seeded Rutgers beat No.