Motherwell prevented Aberdeen from picking up their first league point of the season with a stoppage-time winner at K-Park.
Carla Boyce, who came on for the home side at half time, scored the decisive goal as she headed in from a free-kick.
The late winner a sickener for Aberdeen and means they are still pointless after seven league games.
They remain ninth in the Scottish Women's Premier League, ahead of Montrose on goal difference, while Motherwell are third bottom, six points ahead.
