A player had been dismissed in each of the last three meetings between these sides and a fourth always looked likely once the bruising challenges flew in from the off in this Championship encounter.
Sean O' Driscoll's side shaded the first period with Simon Cox skewing a swerving effort just past the post.
But the game's turning point came only 32 seconds after the break when Blackstock was sent off for what was controversially deemed a deliberate elbow into Richard Keogh's head.
The 10 men found themselves behind nine minutes later when Bryson swept home to round off a flowing move down the right.
The Rams were indebted to goalkeeper Frank Fielding, who made a fine save to deny Simon Gillett at the death and confirm the three points.
Forest, who left out new loan recruit Jermaine Jenas, had struck an early blow in this fixture on the previous three occasions, but they were unable to repeat the feat.
They may well have done, though, had a penalty been awarded when Cox's cross struck Jake Buxton'sarm with referee Robert Madley viewing the contact as accidental.
Any hopes Madley had of enjoying a quiet Sunday afternoon were soon dashed as both sides set the tone with crunching challenges.
Forest came close as Greg Halford's long throw somehow evaded everybody before the City Ground erupted in collective rage as Gareth Roberts became the latest player booked for a wild lunge on Chris Cohen.
Fielding was grateful for another blast of Madley's whistle as the Rams stopper was fouled in the build-up to Danny Collins' header which hit the crossbar.
Conor Sammon and Cox ended the half by trading long-range efforts but the sides went into the break deadlocked.
If Madley had been conservative with his cards in the first 45 minutes, he sent out a huge message seconds after the interval.
Blackstock leapt with Keogh and, as both sides wondered if the decision had gone their way, the Forest striker was shown a straight red for elbowing Derby's skipper in the head.
Blackstock walked off perplexed and the visitors soon made their numerical advantage count.
A lovely move down the right involving John Brayford, Will Hughes and Paul Coutts ended with the latter squaring an enticing centre which Bryson slotted home.
Jamie Ward left the pitch injured but Nigel Clough's side continued to press forward as Bryson forced Lee Camp into a smart stop.
O'Driscoll made a double switch, introducing Billy Sharp and Henri Lansbury, and Fielding almost gifted Forest an equaliser when he fumbled a Halford free-kick before gathering at the second attempt.
But the Rams stopper was alert when called upon again, pushing away Gillett's stinging volley.
Cox and Lansbury were booked in the closing stages to irk the home supporters further before a minor confrontation involving Theo Robinson greeted the final whistle, in what was a fitting end to a fiery affair.
- Sports & Recreation
- Frank Fielding