The crucial victory takes Rovers off the foot of the Championship table and within three points of Forest, with a game in hand over their relegation rivals who occupy the final position of safety.
It was a deserved victory for the visitors, for whom loan signing Frederic Piquionne, a month-long arrival from West Ham this morning, capped the dullest possible first half with a screaming 30-yard strike on the stroke of half-time.
Kyle Bennett doubled that lead within 64 second-half seconds and almost made it 3-0 when his strike was tipped on to a post by Lee Camp. Dexter Blackstock gave Forest hope following a well-worked move just after the hour-mark but it was not enough to prevent an 11th home defeat of the season on a disappointing night for the hosts.
Rovers, in contrast, end a seven-match winless run with what is only their third away success this term.
Forest suffered a setback in the pre-match warm-up when Marcus Tudgay sustained injury, meaning Forest boss Steve Cotterill - like Rovers counterpart Dean Saunders - made three changes.
Robbie Findley came in for Tudgay and it was he who had the first harmless effort after four minutes.
But it was Doncaster who enjoyed the lion's share of possession in the early stages, with Forest - having taken seven points from the last nine on offer - struggling to rise to the occasion.
Blackstock had the first shot on target after 20 minutes, which was comfortably saved at the second attempt by Carl Ikeme.
The chance seemed to breathe the briefest of life into the home side, Garath McCleary going close, but all-in-all it was a lifeless opening half an hour.
The next 15 that followed were hardly an improvement, with both sides playing negative football and the half-time whistle set to bring welcome relief.
That was until debutant Piquionne, out of nowhere in the 44th minute, rifled into the top corner from distance in what was a rare glimmer of top-drawer quality.
Forest were facing an uphill task within two minutes of the restart as Doncaster doubled their advantage.
Joel Lynch and Luke Chambers allowed El-Hadji Diouf to get in at the byline and he crossed for an unmarked Bennett to smash home at the far post.
Bennett almost made it three four minutes later when he was allowed to run and saw his 25-yard shot turned on to the inside of a post by Camp.
The save proved crucial to Forest's hopes as Blackstock reduced the arrears following a flowing move involving Adlene Guedioura and Chris Gunter.
But despite that goal coming with 27 minutes remaining, Reds fans had to wait until the 82nd minute for their side's next chance, McCleary forcing Ikeme into action.
And that was the closest they came to an unlikely leveller.