In a game of few genuine chances, substitute Rinsola Babajide scored an 85th-minute winner for the Reds, who also recorded a maiden clean sheet of the campaign.
That was in no small part thanks to an excellent second-half save by goalkeeper Anke Preuss to thwart Kayleigh Green, which proved to be crucial.
Vicky Jepson took interim charge of Liverpool for the game at Broadfield Stadium with caretaker-manager Chris Kirkland unavailable due to a prior commitment.
An even opening to the encounter meant little in the way of goalmouth action until the midway point of the first half, when Jess Clarke was gifted an opportunity.
A sloppy pass out by Lucy Gillett allowed the Reds No.7 to steal possession but the forward rushed her shot and sent it too close to the Brighton goalkeeper.
Clarke was almost the architect of a breakthrough eight minutes before the interval.
Having beaten two markers to reach the byline, her pull-back to Kirsty Linnett was moved on again towards the supporting Christie Murray but the hosts cleared.
The tempo and threat from both teams increased in the second half and Preuss was called into action 10 minutes in when Kirsty Barton fired a long-range drive on target.
Liverpool’s stopper produced an even better save moments later.
Neat approach work by Brighton freed Green to scamper into a shooting position in the left channel of the area but her low shot across goal was denied by the outstretched leg of Preuss.
And her important intervention proved especially valuable when the Reds themselves claimed the winning goal with five minutes left on the clock.
Babajide had only been on the pitch for a matter of minutes when she tried to play through fellow substitute Courtney Sweetman-Kirk.
The latter’s effort from the edge of the box was blocked but fell for the former to roll a low finish into the bottom left corner and secure three much-needed points for Liverpool.
Liverpool FC Women: Preuss, S. Murray, Bradley-Auckland, Matthews, Robe, Coombs, C. Murray (Babajide, 80), Rodgers, Charles, Linnett (Sweetman-Kirk, 60), Clarke.
Unused substitutes: Kitching, Daniels.