El-Hadji Diouf's second-half penalty secured a point for Doncaster in their fight to avoid relegation and kept Brighton out of the play-off zone.
Diouf stepped up to score coolly from the spot with 10 minutes left after Adam El-Abd was penalised for handball.
Brighton had led at the interval after Craig Mackail-Smith poked home his 11th of the season from close range.
The Seagulls remain a point outside the top six, while Rovers stay bottom, five points from safety.
Blustery conditions and a ragged playing surface made for a scrappy opening, during which home captain Brian Stock hobbled from the field to be replaced by Simon Gillett.
Matters were made worse for Stock's team-mates in the 20th minute when Liam Bridcutt's heavily scuffed effort fell into the path of Mackail-Smith, who managed to prod past Carl Ikeme at the second attempt.
Mamadou Bagayoko almost levelled soon after but his audacious backheel was saved by Peter Brezovan.
The home side missed a further chance to equalise when James Hayter blazed over from inside the area after Gillett's shot was blocked.
Doncaster remained on top at the start of the second period and James Coppinger volleyed narrowly wide before full-back Tommy Spur sent a drilled effort close.
The Seagulls were reduced to breakaway chances, Mackail-Smith failing to get his head to a dangerous centre from substitute Craig Noone.
And just as the home side's efforts began to take on an air of desperation, they were handed a lifeline when El-Abd inexplicably handled a Diouf corner, allowing the Senegal international to slot home from the spot.
Brighton manager Gus Poyet:
"We didn't play well but it was difficult to pass the ball on such a bumpy pitch.
"I'm not making that an excuse because it was the same for both teams and I feel sorry for the Doncaster players because we can go home now while they have to play on it every other week.
"I felt sorry for the fans as well because it was an ugly game - there were some bad decisions for both sides and it wasn't pretty to watch."
Doncaster manager Dean Saunders:
"They had one attack and scored in the first half and it was a terrible goal to concede from our point of view.
"But the lads showed a brilliant attitude to fight back and I thought we were the better team overall.
"I agree the pitch is not good but I thought we played great on it today.
"We may be bottom but we are still in there fighting with games in hand -but we need to score more goals."