Match ends, Derby County 5, Nottingham Forest 0.
Craig Bryson scored three as Derby secured a record-equalling biggest win over rivals Nottingham Forest to revive his team's automatic promotion hopes.
The Rams had not scored in four matches but led when Bryson bundled a shot in after a scramble.
He doubled the lead when he finished from Chris Martin's lay-off before Jeff Hendrick finished a counter-attack to make it three.
Johnny Russell drove in a fourth before Bryson scored a penalty.
Bryson's hat-trick was a first for a Derby player in this fixture since Steve Bloomer's treble in a victory by the same scoreline in 1898.
While the Rams have not given up hope of catching second-placed Burnley, the play-off hopes of Billy Davies' Nottingham Forest have been hit by a miserable run that has now seen them fail to win in seven league matches.
Steve McClaren's Derby had fallen away from the top two by failing to score in a winless run of four games but they took the lead after five minutes when Bryson's shot flew in off Danny Collins.
Radoslaw Majewski had a curling shot held by Derby goalkeeper Lee Grant as the visitors began to control possession but they found themselves two behind when Bryson finished from Martin's pass.
Eight minutes before the break, the Rams made it three when they broke quickly from a Forest corner and Patrick Bamford played through for Hendrick to shoot under goalkeeper Karl Darlow.
Substitute Russell thumped in the fourth from just outside the area after a heavy spell of pressure.
Darlow pushed away a flick from Martin but then gave away a penalty for a clip on Bamford to allow midfielder Bryson to convert from the spot for his 15th league goal of the season.
Derby head coach Steve McClaren:
"We knew if we kept doing the right things the end product would come and there's no better day to do it than today in front of 33,000 fans.
"I think this win is for the Derby fans.
"We got Nottingham Forest at a good time with all the injuries but I think this is the best win and probably the most satisfying purely because we kind of controlled the whole game."
Nottingham Forest assistant manager David Kelly:
"Huge credit to Steve and his group, they thoroughly deserved the victory but we were disappointed in how we defended.
"It was a disappointing catalogue of goals we gave away and what we were working on during the week was disappointing in how it was executed on the day.
"It's a huge, huge game in the season and we're disappointed we've let the fans down. We only had a fit group of 18 we brought today but that's not an excuse, it's just the facts of what's going on."
- 34ThorneBooked at 18mins
- 4BrysonSubstituted forHughesat 85'minutes
- 9MartinSubstituted forSammonat 82'minutes
- 10WardSubstituted forRussellat 39'minutes
- 13FoxBooked at 73mins
- 16LascellesBooked at 85mins
- 6MoussiSubstituted forHendersonat 45'minutes
- 31CoxBooked at 34minsSubstituted forDerbyshireat 79'minutes
- 21PatersonSubstituted forHalfordat 64'minutes
- 29de Vries
- Michael Naylor
- Shots on Target
Second Half ends, Derby County 5, Nottingham Forest 0.
Attempt missed. Radoslaw Majewski (Nottingham Forest) right footed shot from outside the box misses to the left.
Attempt missed. Matt Derbyshire (Nottingham Forest) right footed shot from the centre of the box misses to the right. Assisted by Greg Halford.
Attempt missed. Jamaal Lascelles (Nottingham Forest) header from the centre of the box is too high. Assisted by Daniel Fox with a cross following a set piece situation.
Greg Halford (Nottingham Forest) wins a free kick in the attacking half.
Foul by Jake Buxton (Derby County).
Jamie Mackie (Nottingham Forest) wins a free kick in the defensive half.
Foul by Will Hughes (Derby County).
Substitution, Derby County. Will Hughes replaces Craig Bryson.
Jamaal Lascelles (Nottingham Forest) is shown the yellow card for a bad foul.
Foul by Jamaal Lascelles (Nottingham Forest).
Craig Bryson (Derby County) wins a free kick in the attacking half.
Foul by Daniel Fox (Nottingham Forest).
Patrick Bamford (Derby County) wins a free kick in the attacking half.
Greg Halford (Nottingham Forest) wins a free kick on the right wing.
Foul by George Thorne (Derby County).
Substitution, Derby County. Conor Sammon replaces Chris Martin.
Foul by Darius Henderson (Nottingham Forest).
Richard Keogh (Derby County) wins a free kick in the defensive half.