Match ends, Nottingham Forest 3, Brighton and Hove Albion 0.
Nottingham Forest scored two late goals to seal victory as Brighton missed the chance to go top of the table.
Forest led in controversial fashion through substitute Zach Clough's shot, much to the disgust of the Seagulls, who felt Britt Assombalonga got the final touch from an offside position.
Brighton went close to levelling through Lewis Dunk, substitute Solly March and Anthony Knockaert.
But Ben Osborn and Clough's late injury-time penalty sealed victory.
Osborn's simple 89th-minute tap-in, after keeper David Stockdale made a mess of Liam Rosenior's backpass, settled the nerves at the City Ground following a run of three defeats in Forest's previous four Championship matches.
And Clough's second goal for the club, eight minutes into stoppage time following a foul by Dunk on teenage striker Ben Brereton, added a comprehensive feel to a result which lifted them six points clear of the relegation zone.
Brighton - who would have gone above leaders Newcastle with a win - offered little until they fell behind, but were still a long way short of their best.
They produced just one shot on target in a largely uneventful first half, with Forest keeper Jordan Smith making a decent save from the lively Knockaert.
Seagulls top scorer Glenn Murray did have the ball in the net when he smashed in from close range after a smart turn and shot following a long throw, but an 18th goal of the season was ruled out for handball.
Clough's opener put the hosts ahead and they were able to resist Brighton's best spell of the game soon after and close out the win late on.
Nottingham Forest interim boss Gary Brazil: "In key moments in the game we were strong. If we have got a little bit of luck, I think we have earned it. Our all-round performance was one that deserved victory.
"It was not a defining moment in the game, because there was still a lot of football to play.
"In the first half we got a real grip of the game and then we pushed on from that in the second half.
"I am chuffed to bits for the players and the staff, but particularly for the fans who stuck with us throughout the game.
Brighton manager Chris Hughton: "Whether the referee knew if Assombalonga had touched the ball or not, I am not so sure. He must have been made aware of it.
"I was disappointed that the goal was not overturned. It looked as though he was in an offside position. The person with the best view of that is the linesman and you would expect him to give that decision.
"We got through to half-time without being at our best. We knew we needed to raise our game, which we have been able to do in the past.
"We did do that, but they got the first goal which made things tougher. Then we conceded really poor goals after that."
- 17PereiraSubstituted forCloughat 59'minutes
- 19WardSubstituted forTshibolaat 90+6'minutes
- 9AssombalongaSubstituted forBreretonat 77'minutes
- 5DunkBooked at 63mins
- 23RoseniorBooked at 90mins
- 6StephensBooked at 45mins
- 14SidwellSubstituted forNorwoodat 67'minutes
- 15MurphySubstituted forMarchat 65'minutes
- 9BaldockSubstituted forHemedat 72'minutes
- Oliver Langford
- Shots on Target
Second Half ends, Nottingham Forest 3, Brighton and Hove Albion 0.
Liam Rosenior (Brighton and Hove Albion) is shown the yellow card.
Goal! Nottingham Forest 3, Brighton and Hove Albion 0. Zach Clough (Nottingham Forest) converts the penalty with a right footed shot to the centre of the goal.
Penalty conceded by Lewis Dunk (Brighton and Hove Albion) after a foul in the penalty area.
Penalty Nottingham Forest. Ben Brereton draws a foul in the penalty area.
Substitution, Nottingham Forest. Aaron Tshibola replaces Jamie Ward.
Delay over. They are ready to continue.
Delay in match Shane Duffy (Brighton and Hove Albion) because of an injury.
Attempt saved. Shane Duffy (Brighton and Hove Albion) header from the centre of the box is saved in the centre of the goal. Assisted by Liam Rosenior with a cross.
Goal! Nottingham Forest 2, Brighton and Hove Albion 0. Ben Osborn (Nottingham Forest) right footed shot from the centre of the box to the centre of the goal.
Attempt missed. Anthony Knockaert (Brighton and Hove Albion) header from the centre of the box is just a bit too high. Assisted by Solly March with a cross.
Attempt missed. Oliver Norwood (Brighton and Hove Albion) right footed shot from outside the box is high and wide to the right. Assisted by Anthony Knockaert.
Corner, Nottingham Forest. Conceded by Lewis Dunk.
Foul by Oliver Norwood (Brighton and Hove Albion).
Ben Brereton (Nottingham Forest) wins a free kick in the attacking half.
Attempt blocked. Zach Clough (Nottingham Forest) right footed shot from outside the box is blocked. Assisted by Ben Brereton.
Corner, Brighton and Hove Albion. Conceded by Daniel Fox.
Substitution, Nottingham Forest. Ben Brereton replaces Britt Assombalonga.
Attempt missed. Lewis Dunk (Brighton and Hove Albion) header from the centre of the box is close, but misses the top left corner. Assisted by Oliver Norwood with a cross following a corner.