NEAL MAUPAY hit a leveller with virtually the last kick of the game to break Palace’s hearts.
The Eagles thought they had won this derby when Wilfried Zaha fired home a penalty just before half-time.
But when Maupay raced onto a hopeful punt from Joel Veltman in the fifth minute of injury time, the Frenchman kept his composure to lift the ball over Vicente Guaita and into the net.
It sparked wild celebrations from Graham Potter and his Albion bench, while the travelling fans threw a blue flare onto the pitch.
A delirious Maupay then chucked his shirt into the away crowd, moments after there had been a row between Seagulls keeper Robert Sanchez and James McArthur.
It was a real smash and grab from Potter’s side who were not at their best.
The last-gasp goal was a role reversal of the one Christian Benteke netted for Palace in their 2-1 win at the Amex last season.
Brighton were bidding to reach the summit of the top flight for the first time in their 120-year history here with a victory.
FREE BETS: GET OVER £2,000 IN NEW CUSTOMER DEALS
They did not manage it but Maupay’s heroics – which saw him net his fourth of the season – did keep up their unbeaten run to the campaign.
It was tough to take for Palace boss Patrick Vieira, whose side had been the better of the two and had looked to have done enough until Maupay struck.
The Seagulls were dealt a huge blow ahead of the game with talismanic Yves Bissouma failing to recover from a knee injury.
The Malian raised eyebrows last week when naming himself as the best midfielder currently playing in the Premier League.
Whether he is at that level yet is debatable.
Vieira, himself a midfield icon of our top flight, is certainly a fan and hailed the 25-year-old as “one of the league’s best midfielders” pre-match so will have been relieved to see him miss out.
Despite the two clubs’ rivalry, there had been a lot of love between the two managers ahead of the game.
Graham Potter spoke of how “fantastic” it was to see legendary players like Vieira entering management.
While his French counterpart claimed Potter was “a good example” for him to follow in how he transformed Brighton’s style after succeeding successful pragmatist Chris Hughton.
The two bosses had a warm embrace before kick-off – but it did not take long for the rough and tumble to begin once the game began.
New-boy Joachim Andersen instantly endeared himself to the Palace ultras by dragging Maupay to the ground after Palace had been given a free-kick for handball.
While Joel Ward had the crowd oohing and aahing as he put in a full-blooded challenge to send Danny Welbeck flying.
Palace dominated the first half with their new possession game, but did not muster much in terms of chances.
Odsonne Edouard was handed his first start and had a sniff on 20 minutes when he received the ball on the edge of the area, but his shot was straight at Robert Sanchez.
Brighton were struggling to get into it despite their confidence from a stellar beginning to the campaign.
Leandro Trossard finally brought about their first attempt on the half hour as he flicked Pascal Gross’s cross wide at the near post.
Then came a flash point as Welbeck raced onto a long punt from Sanchez but could not fire his dinked effort past Vicente Guaita.
The ex-Manchester United and Arsenal man however was calling for a penalty, claiming Ward had fouled him as he ran in on goal.
Replays suggested it was clumsy, but referee Andre Marriner was not convinced.
Marriner was won over by a foul on Gallagher at the other end right on half-time though.
Gallagher’s positive run into the box was the one real moment of attacking quality in the first half and when Trossard barged into him after Marc Cucurella had already had a nibble, the Chelsea loanee hit the deck.
Zaha then did what he always does when playing Brighton, netting his eight goal in 14 appearances against them by sending Sanchez the wrong way from the spot.
He cupped his ears in celebration as seven eighths of Selhurst Park went barmy.
It was a bad end to a poor half for the visitors and Potter responded by bringing on Steven Alzate for Dan Burn at the break.
But the young Colombian did not last longer than 20 minutes as he damaged his ankle under the weight of Jordan Ayew and had to be replaced himself by Jakub Moder.
Brighton’s injury problems increased when Welbeck went down and was forced off.
Palace should have killed the game off when a driving run from Gallagher saw sub Christian Benteke feed Ayew, but the Ghanaian fired wide.
The hosts then somehow found themselves pegged back right at the death when Maupay kept a cool head – sparking everyone to lose theirs.
Read our Football news live blog for the very latest rumours, gossip and done deals