Brighton's last league loss was a 2-0 home defeat by Brentford on 10 September
Brighton went top of the Championship and made it 15 games unbeaten with a win at 10-man Blackburn Rovers.
Seagulls defender Shane Duffy headed in Oliver Norwood's corner against his former side to put the visitors ahead.
Dale Stephens' volley after the break doubled the lead before Rovers' Sam Gallagher fired in from close range.
Brighton substitute Glenn Murray chipped in to seal the win after Blackburn's Gordon Greer was sent off, before Gallagher grabbed a consolation.
Murray's 13th league goal of the season and first away from home this campaign, came after Rovers goalkeeper Jason Steele dropped Lewis Dunk's shot at the striker's feet.
Any chance of a comeback by the hosts had already been made more difficult at 2-1, when ex-Brighton captain Greer was shown a second yellow for a foul on Bournemouth loanee Murray 16 minutes from full-time.
Gallagher smashed in his ninth Championship goal this season and second of the evening after racing clear in stoppage time, but it was too late for Owen Coyle's struggling side in front of a season-low crowd of 9,976 at Ewood Park.
Rovers have now lost 11 of their 21 Championship fixtures and Cardiff's win over Wolves ensured they slipped into the relegation zone.
In contrast, Brighton have been defeated in just seven of their past 68 league games in a run stretching back to May 2015, but will be replaced by Newcastle at the summit if the Magpies win at Wigan on Wednesday.
Duffy's prolific record against Blackburn
Duffy, who arrived on the south coast in August, has now scored four times against Rovers this season - three of them own goals.
Shane Duffy (r) played for the Republic of Ireland at Euro 2016
The 24-year-old turned into his own net in a 3-0 defeat at Wigan on 13 August.
Four days later Duffy scored two first-half own goals and was then sent off in stoppage time in a 2-1 loss at Cardiff - his final league match for the Lancashire club.
Blackburn manager Owen Coyle told BBC Radio Lancashire:
"I thought we started the game really well on the front foot against a team I would say along with Newcastle look very, very big favourites certainly for automatic promotion.
"We certainly made one or two chances, but we accepted they were very dangerous on the counter-attack. At 2-1. We felt we were right back in it with a chance to turn the game on its head.
"But, it's a huge turning point when Gordon picks up the second yellow card. There was certainly contact and it leaves us with 10 men against one of the most difficult sides to face.
"They battled away and kept going, giving everything they could. There's plenty of heart and plenty of spirit, but we're conceding far too many goals.
Brighton manager Chris Hughton told BBC Sussex:
"That was closer than what we deserved and what it should have been. That's my only disappointment of the night.
"But, I thought we broke really well at times and at certain stages of the game, we could have been really out of sight.
"Ultimately, it's about three points and every away victory is a valued victory. No games are easy on the road so I'm delighted with the three points."
