A battling Forest performance saw them take a much deserved share of the points with a last-minute equalizer.
It took 20 minutes for the game to get going but Forest improved as the half progressed, creating most of the chances and looking the more likely side to score while Lee Camp had little to do in the first 45 minutes.
Brighton made their only shot on target pay when they took the lead in the 63rd minute but apart from that it was nearly all Forest, who finally got their reward with a stoppage time equaliser.
An unchanged Forest side started in lively fashion, with the home crowd urging them on from the outset.
Brighton passed the ball around patiently, but mostly in midfield and Forest failed to take advantage and steal it from them.
But the cautious play from both teams was far from conducive to exciting football and not a shot either on or off target was produced for over 20 minutes.
Some good build-up play by Forest saw the ball cleared by Brighton, but only as far as Adlene Guedioura who, from long range, sent the ball flying in the right direction, but his effort was well wide.
And down the other end Ashley Barnes cut in from the right to line up a shot, but his effort was also wide of the target.
Good work from Guedioura saw him work his way in from the right and send the ball across the face of goal and it was deflected out for a corner.
The Forest bench and a large number of the crowd thought they had won a penalty when Lewis Dunk took Guy Moussi out right on the edge of the penalty area but the referee decided the foul had taken place just outside and awarded Forest a free kick.
Andy Reid put the ball round the wall and as Peter Brezovan dived to his right the ball flew off the far post to safety.
Guedioura looked like he was going to shoot for goal when he got the ball away from a Brighton player on the right but instead he crossed the ball towards Dexter Blackstock, but he put too much behind his shot and it went wide.
And as Forest continued to put on the pressure Blackstock got above his man but headed the ball wide from Reid's cross.
Forest came close again following a corner when the ball was cleared out to Guedioura who chested it down and his shot had the keeper beaten but he thumped the ball just wide of the post.
The home crowd had to wait ten minutes before the second half really came to life with a great break by McCleary down the right. His low cross almost fell to Guedioura before being half cleared to Moussi who picked out Reid on the left but his cross was gathered by Brezovan.
Ashley Barnes should arguably have been off the pitch after first bringing McCleary down in midfield and a minute later felling Chris Gunter to the right of the penalty area but the referee had failed to show a yellow card for the first offence.
Brighton took the lead just after the hour mark from a free kick by Rodgiguez Vincente from 35 yards out. The ball was chipped into the six-yard box as Sam Vokes made the run in, got above Camp and sent the ball in with a glancing header.
Forest reacted well and pushed forward with another powerful, long-range shot from Guedioura causing problems, but this time it went straight at the keeper who struggled to hold it.
And a good break down the right by McCleary came close to putting Forest level when his shot from a tight angle was deflected and then Brezovan turned the ball round for a corner.
Marcus Tudgay became Forest's first substitute in the 72nd minute, replacing Majewski to give Forest an extra front man.
Luck was not on Guedioura's side as he saw another long-range rocket hit the inside of the post and come back out.
McCleary became the second Forest player to be replaced when he made way for Ishmael Miller with eight minutes remaining.
Forest were denied again when the ball came into a crowded box where Miller's effort was bundled towards goal and came off the post before being put out for a corner.
In a final change aimed at getting a late equaliser, Greg Cunningham was replaced by Lewis McGugan in the 89th minute.
Brighton had to play the five minutes of stoppage time with ten men when substitute Matt Sparrow was sent off for a second yellow card.
Four minutes into stoppage time Forest got their deserved equaliser when Joel Lynch put the ball away from six yards out to score against his former club.
Forest: Camp, Gunter, Chambers(c), Lynch, Cunningham(McGugan 89min), McCleary(Miller 82min) Guedioura, Moussi, Reid, Majewski(Tudgay 71min), Blackstock.
Subs not used: Smith(GK), Wootton,
Bookings: Chambers 53min
Scorer: Lynch 90+4min
Brighton: Brezovan, Maattock, Greer(C), Dunk, Navarro, Barnes, Calderon, Vicente(Razak 78min), Vokes(Agdestein, 89min), Lualua(Sparrow 50min), Bridcutt
Subs not used: El-Abd, Ankergren,
Bookings: Bridcutt 49mn, Barnes 61min, Sparrow 72min, 90min RED CARD
Scorer: Vokes 63min
Referee: Michael Naylor, South Yorkshire
Attendance: 21,249 Away attn: 2,045