Albion showed their mettle again to claim an eighth win out of ten, thanks to Lee Steele.
The substitute's first goal for the club on 63 minutes clinched a hard-fought victory for the Seagulls at Feethams.
Nathan Jones had earlier given Micky Adams' men a dream start with a fourth-minute opener before the in-form Glenn Naylor equalised for Darlington on 34 minutes.
Pouring rain and a wet pitch made life difficult for both sides, but they served up an entertaining contest for a crowd of 3,637.
Jones pounced to drill home his fifth of the season when the Darlington defence failed to clear a Gary Hart cross.
Albion seemed to be in control until Naylor capitalised on a kind rebound off Matthew Wicks to slot his fifth goal in the last six games.
Albion came under pressure early in the second half after Steele replaced Charlie Oatway just before the break.
Keeper Michel Kuipers somehow kept out an Adam Reed header for the second time in the match.
Just as it looked as if Darlington were getting on top, Steele delivered the decisive blow.
The former Shrewsbury marksman, yet to start a match for the Seagulls, converted a cross from fellow sub Paul Brooker, on in place of Bobby Zamora.
It was only Darlington's third home defeat since May 1999 and Albion have now lost just once in 13 outings to keep up the pressure on leaders Chesterfield.
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