Albion came away empty handed on a night of frustration at relegated Sheffield United.
Missed chances, a VAR decision that went against Jakub Moder, and a poorly conceded goal all conspired to leave the Seagulls still looking over their shoulders in the battle to beat the drop.
While the first half was evenly matched, United took the lead through David McGoldrick, but it was a different story after the break as Albion laid siege on the hosts' box. Sadly it couldn't be converted to goals as Graham Potter's side lost on the road for only the third time in the Premier League this year.
Albion had created the game's first opening on 12 minutes when Yves Bissouma broke from his own half with a driving run before releasing Neal Maupay. As the striker honed in on goal, Blades keeper Aaron Ramsdale was equal to the danger and the ball went out for a corner.
The hosts broke the deadlock seven minutes later when Ben Osborn sent in a deep cross from the left. Two failed clearances saw the ball fall to McGoldrick, who made no mistake with his shot on the turn from close range. Having also lost possession cheaply before United broke, it was an uncharacteristic goal for Albion to concede.
With their relegation already confirmed, United were playing seemingly pressure-free and continued to press the Albion defence. Brewster and Jayden Bogle both had shots blocked as the visitors failed to get their usual passing game going.
As the game reached the half-hour mark, Albion did get more of a foothold in the game. Adam Webster headed over from a Pascal Gross corner, while Bissouma drove forward once again but his effort flew wide of the target.
Gross and Leandro Trossard also combined to set up Moder, whose cross eluded everyone as it flashed across the six-yard box.
Albion showed their second-half intentions immediately from kick-off as Moder broke forward to tee up the increasingly influential Adam Lallana, but his low effort was comfortably saved by Ramsdale.
Lallana and Danny Welbeck then combined to tee up Maupay, who was again foiled by Ramsdale low to his right.
The pressure on the Blades goal looked like it had finally paid off in the 56th minute when Welbeck and Webster kept a Gross corner alive in the six-yard box. Moder was on hand to tuck the ball home, however VAR ruled him offside in the build-up to the goal.
It was now one-way traffic; Lallana added a Moder knock-on wide while a trademark Bissouma long-range drive flew inches wide.
Sub Alireza Jahanbakhsh then sent in a teasing cross into the box but the bounce sent the ball beyond the diving Welbeck at the far post.
The Iranian then produced an excellent piece of wing play but his cross was put over the bar by Maupay from three yards out. In the striker's defence, the ball was fired in at some pace but it was a miss the Seagulls were left to rue.
Jose Izquierdo entered the fray late on, for his first appearance in two years, and his first contribution was a 25-yard dipping effort that was pushed away by Ramsdale for a corner.
Albion huffed and puffed as the game entered injury time, but the Blades held on for their fourth home win of the season.
Brighton: Sanchez, Webster, Dunk, Veltman, Trossard (Izquierdo 82), Bissouma, Lallana, Moder (Jahanbakhsh 66), Gross (Connolly 66), Maupay, Welbeck.
Subs not used: Steele, Burn, Mac Allister, Alzate, Propper, Zeqiri