LEEDS United set an unwanted club record of 11 home games without a win as Brighton substitute Bobby Zamora struck an 89th-minute winner for the only unbeaten team in the top four divisions.
It came after Leeds, having used all their replacements, were reduced to 10 men following injury to goal scorer and central defender Liam Cooper.
Zamora was played in down the left channel by Gaetan Bong and chipped the ball past Marco Silvestri to inflict a third home defeat of the season on Leeds, who have drawn the other three at Elland Road.
Following the international break, coach Uwe Rosler made three changes to the Leeds team and adopted a 4-1-4-1 formation as the visitors played 4-4-2.
Charlie Taylor missed his first game of the season - thought to be through illness - and was replaced at right-back by Scott Wootton as Gaetano Berardi moved to left-back.
Jordan Botaka came in to make his full home debut in place of Sunderland loanee and former Brighton winger Will Buckley with Stuart Dallas on the opposite flank.
Tom Adeyemi came in for Luke Murphy and protected the defence.
Lewis Cook, recovered from a shoulder injury sustained with England Under-19s, drove Leeds forward from central midfield in the early stages but Brighton struck from their first attack in the 14th minute, Solly March drilling a low shot beyond Silvestri after being played in by Beram Kayal.
Leeds struck back and lone striker Chris Wood went close to converting a low cross from Stuart Dallas before the equaliser came in the 22nd minute. Lewis Dunk fouled Wood 30 yards out and Alex Mowatt swung in a free-kick which central defender Cooper flick-headed inside the far post for his first goal in over 11 months.
Wood should have given Leeds the lead but sent a free header wide from six yards as he connected with a free-kick from Mowatt.
Brighton suffered a blow before the break when captain Gordon Greer withdrew after taking a knock to the head and was replaced by Uwe Hunemeier.
Leeds twice went close after the break as Wood, with his back to goal, instinctively flicked the ball over the bar as it rebounded off a defender at a corner. Then Mowatt charged down a clearance from goalkeeper David Stockdale but the ball rebounded narrowly wide.
Brighton were not done and March cut inside to fire a shot against the bar and, after maintaining the pressure, Silvestri stuck out a leg to keep out a back-heel from Tomer Hemed.
Both sides made attacking changes in their bid for victory but Cooper limped off in the 83rd minute after damaging his left knee tackling Kayal. Cooper was helped down the tunnel as Wootton moved across and substitute Sam Byram dropped to right-back.
Leeds’ woes continued as Zamora struck the winning blow for the table-topping Seagulls.
Leeds head coach Uwe Rosler bemoaned his luck, saying: “Things are just not going for us at the moment. There were three key moments in the game. They scored from their first attack and I feared the worst but we showed terrific character and got a quick equaliser.
“The second key moment was when Chris Wood didn’t take his unbelievable opportunity. The game looked like ending 1-1 so we brought on Mirco Antenucci and Will Buckley to try and win it but the third key moment was Liam Cooper’s injury, leaving us with 10 men.
“Having said all that, we can’t feel sorry for ourselves. There are a lot of people far worse off than us so we have to pick ourselves up and go again. I feel a bit sorry for the players, supporters and owner. When you invest as much as the players do in training and get so little back it’s disappointing.”
Delighted Brighton manager Chris Hughton said: “We deserve to be where we are at the moment. We were probably not at our best today but we showed a willingness to fight to the end and get the right result. Bobby Zamora came on and scored about ten minutes later and I am delighted for him.
“We know what he gives us but it was a team effort at that stage of a game that seemed to be petering out into a draw. Bobby wasn’t up to speed in pre-season, so we knew it would take time, but we have been able to use him at the right times. He gave us exactly what we needed when he came on. The players very much wanted to win the game and it showed.”