GARETH Roberts returned to the Keepmoat Stadium to haunt his former club as Rovers missed the opportunity to move closer to safety.
Left back Roberts rounded off a flowing second half move from Derby after Theo Robinson had given the Rams the lead before the break.
El Hadji Diouf raised hopes of a comeback when he turned in the box and fired past Frank Fielding but it proved to be no more than a consolation for below par Doncaster.
Rovers struggled to settle right from the off and it was no surprise when Robinson latched onto a long ball over the top and prodded it past the oncoming Carl Ikeme with 13 minutes on the clock.
Freddie Piquionne headed Rovers' best chance of the first half straight at Fielding but the hosts struggled for any sort of momentum or fluidity in their play.
They started the second period in brighter fashion but Roberts' goal, a neat drilled finish from inside the box, took the wind out of Doncaster's sails.
Diouf halved the deficit midway through the half when a hopeful free kick was flicked on by Giles Barnes into his path and the Senegalese forward finished clinically from close range.
But Rovers could have few complaints with the disappointing outcome - outfought by a determined Derby side and perhaps showing signs that recent games have caught up with them.