Gemma Fraser gave Chesham the lead at Buckingham Athletic but this was short-lived as Heather McDonnell swiftly brought the Dons back on level terms with a volley on the turn.
After the break, Kara Howes blocked out an effort from Chesham’s Natalie Adams but then Natasha Smith crossed the ball into the box for Niamh Euman to head home what proved to be the winner for the underdogs.
Charly Clarke, Heather Barrett and McDonnell all had chances saved, while Amelia Hazard headed over as the Dons failed to equalise a second time.
