Sam Griffiths' side suffered a heartbreaking end to the opening game of the season as Burnley scored eight minutes into injury time to snatch a 3-2 win.
The Ewe Rams looked to have been holding out for a deserved draw, but with seconds remaining Dom Cooper found space in the box to fire past Imogen Maguire.
It was harsh on Derby, who had twice led through Amy Sims and looked to have done enough to earn a point in front of a bumper crowd of 523.
In an entertaining encounter, the visitors began on the front foot and forced Maguire into a handful of saves during the opening stages.
Evie Priestley was the first to test Maguire with Olivia Wilson and Millie Ravening following suit, but Derby’s number one held firm to deny all three.
Having soaked up the pressure for the best part of half an hour, it was the Ewes who struck first through the ever-reliable Amy Sims.
Outside the area, Sims caught Lauren Bracewell off her line and looped an audacious effort beyond the opposition goalkeeper’s reach and into the back of the net to open the scoring with 30 minutes on the clock.
Burnley turned up the heat again after going behind and came close to equalising moments before half-time, but Evie Priestley’s dangerous ball across the face of goal was cleared to signal the end of the half.
Becky McGrother fashioned an early goal scoring opportunity in the second half as she took aim from range in the 46th minute, but Bracewell held onto the ball well on this occasion.
Just moments later the Clarets were level through Ellie May. Almost a carbon copy of Sims’ opener, May’s effort from the edge of the area dipped over Maguire in the 51st minute to make it 1-1.
Hannah Ward broke through on goal six minutes later but failed to navigate her shot on target as it slipped just wide of the near post.
Derby then restored their lead three minutes later as Sims bagged her brace. After outmuscling her opponent, the right-back fired a shot across goal the face of goal which nestled into the bottom left hand corner.
Things were level again in the 75th minute through Priestley. The forward latched onto the end of an inviting cross to volley home at the far post for the visitors.
Priestley had an opportunity to score her second goal of the afternoon five minutes into injury time, her shot well-saved by Maguire again to keep the score level.
One minute later, however, Burnley stole the winner. Dom Cooper worked some space towards the right hand side of the penalty area before finishing well past the onrushing Maguire to seal three points for the opposition.
The Ewes will be disappointed in defeat, but not disheartened. It was a fantastic performance which certainly would have been rewarded on another day.