Only two points separated the sides at the end of the second and third quarters.
Derbyshire upped the pressure and went ahead by double figures early in the fourth.
However, the Eagles came storming back to tie the game, only to then see another close game slip away.
“I cant ask much more from the players,” said head coach Bob Martin.
“We are down to seven fit players and just seem to run out of gas.”
Paul Walsh (22) and Mathew Martin (17) led the scoring for the Doncaster club.
Eagles, who won back-to-back promotions in their first two seasons at senior level, sit one place and two points above bottom club Newham Neptunes.