Match ends, Cardiff City 2, Brighton and Hove Albion 1.
Brighton boss Chris Hughton said he was "angry" over an offside claim in the build-up to Sol Bamba's last-minute winner, which earned Cardiff City a second win of the season.
The visitors, who took the lead via Lewis Dunk's early header before Callum Paterson's equaliser, had Dale Stephens sent off for a lunge at Greg Cunningham after 34 minutes.
After some superb defending, Brighton looked like they would escape with a point but Cardiff twice hit the woodwork in the build-up to Bamba's strike.
"I don't think Sol Bamba looked offside, he was offside!" said Hughton. "I understand the sending off, some would give it, some wouldn't, but on the winning goal he is offside and for me that is not a difficult decision to make.
"We have a linesman in a very good position when the ball comes back in, so for me, I am more angry with the second decision than the first one."
Having won three successive games in October, Brighton surrendered a winning position for the first time this season and have now had two consecutive defeats.
Century up for Warnock
On his 100th game in charge of the Bluebirds, veteran boss Warnock made clear that he did not consider the visit of Brighton a "must-win" game.
Cardiff have played all of the Premier League's top five in their opening 11 fixtures back in the top flight and were beaten by Leicester City last weekend.
A home contest with Brighton seemed to be an opportunity for Cardiff to change their fortunes, but they continued an unfortunate trend of conceding early to give themselves a tough task.
Tottenham, Arsenal, Liverpool and now Brighton have all scored against the Bluebirds inside the opening 11 minutes this season.
Already criticised by their manager for conceding "sloppy goals", Cardiff surrendered the advantage to Brighton within six minutes and in the simplest of manners, the eighth time in 12 league games this term they have conceded first.
The goal was a well delivered set-piece; a free-kick from Solly March headed home emphatically by Dunk who lost his marker Bamba with ease.
It was a fitting response from Dunk to the news he has been called up by England manager Gareth Southgate.
Brighton could have extended their lead when it was still 11 versus 11, but Glenn Murray's snap shot was held by Neil Etheridge as Cardiff looked to respond.
The Bluebirds received a slice of luck with their equaliser, with Kadeem Harris' powerful run resulting in a cross that deflected off Gaetan Bong and perfectly into the path of Paterson, who nodded home to level.
This was the first time this season that Brighton have given up an advantage from a winning position, leaving Manchester City as the Premier League's only side who have yet to surrender a lead.
Stephens sees red to boost Bluebirds
Albion won all of their league fixtures in October 1-0 against Wolves, Newcastle and Southampton.
However, after conceding an equaliser and a contentious red card, the match then spun in Cardiff's favour in the 33rd minute.
Stephens lunged at Cardiff defender Cunningham. Contact was minimal, but the velocity of the tackle prompted Martin Atkinson to show a straight red card.
Brighton then battled to hold on as Victor Camarasa twice tested Mat Ryan, and it appeared the Bluebirds would be denied before their dramatic winner in the last minute of normal time.
Bamba, created chaos in the penalty area with a bicycle kick that struck the post, with Ryan brilliantly tipping Paterson's rebound onto the crossbar.
However, Bamba reacted quickest, blasting home to earn Cardiff a vital win.
Man of the match - Kadeem Harris
Dunk head above the rest
- Brighton have won just one of their past 20 Premier League matches away from home (D5 L14), with that victory coming against Newcastle in October.
- Cardiff have conceded the first goal of the game on more occasions than any other team in the Premier League this season (nine).
- Eleven of Lewis Dunk's 13 league goals for Brighton have been headers.
- Cardiff's Callum Paterson has scored three goals in his past four league appearances, after netting in just one of his previous 14.
- Neil Warnock took charge of his 100th match as Cardiff City boss (W46 D21 L33), with his side beating Brighton for the first time in three attempts during his reign at the club (W1 D1 L1)
After the international break, Cardiff travel to Everton before hosting Wolves. Brighton will host Leicester in two weeks before travelling to Huddersfield.
- 5Ecuele Manga
- 4MorrisonSubstituted forPeltierat 70'minutes
- 18CunninghamBooked at 71mins
- 23K Harris
- 8RallsSubstituted forReidat 76'minutes
- 11MurphySubstituted forHoilettat 72'minutes
- 13PatersonBooked at 35mins
- 6StephensBooked at 34mins
- 20MarchSubstituted forBissoumaat 39'minutesBooked at 90mins
- 17MurraySubstituted forAndoneat 63'minutes
- Martin Atkinson
- Shots on Target
Second Half ends, Cardiff City 2, Brighton and Hove Albion 1.
Kadeem Harris (Cardiff City) wins a free kick on the left wing.
Foul by Martín Montoya (Brighton and Hove Albion).
Yves Bissouma (Brighton and Hove Albion) is shown the yellow card.
Bobby Reid (Cardiff City) wins a free kick in the defensive half.
Foul by Martín Montoya (Brighton and Hove Albion).
Víctor Camarasa (Cardiff City) wins a free kick in the defensive half.
Foul by Beram Kayal (Brighton and Hove Albion).
Foul by Callum Paterson (Cardiff City).
Martín Montoya (Brighton and Hove Albion) wins a free kick in the defensive half.
Attempt missed. Callum Paterson (Cardiff City) left footed shot from the right side of the box is close, but misses to the left.
David Junior Hoilett (Cardiff City) wins a free kick in the defensive half.
Foul by Gaëtan Bong (Brighton and Hove Albion).
Goal! Cardiff City 2, Brighton and Hove Albion 1. Sol Bamba (Cardiff City) right footed shot from very close range to the high centre of the goal.
Attempt blocked. Callum Paterson (Cardiff City) right footed shot from the centre of the box is blocked. Assisted by David Junior Hoilett.
Sol Bamba (Cardiff City) hits the right post with a right footed shot from the centre of the box. Assisted by Bruno Ecuele Manga with a headed pass.
Attempt blocked. Bruno Ecuele Manga (Cardiff City) left footed shot from the centre of the box is blocked. Assisted by Aron Gunnarsson.
Attempt blocked. David Junior Hoilett (Cardiff City) right footed shot from the centre of the box is blocked. Assisted by Aron Gunnarsson.
Corner, Cardiff City. Conceded by Mat Ryan.