If Albion go on to defy the odds stacked against them by surviving in the Championship this season, they are bound to reflect on Boxing Day as a significant turning point.
There did not look like being much in the way of festive cheer for Mark McGhee and his side deep into the second half at a frosty Withdean.
Gillingham, courtesy of Andrew Crofts' first senior goal, were on course to close within a point of the Seagulls. As if that was not worrying enough, Cardiff were beating Wolves and Nottingham Forest had just recovered from a two-goal deficit to be drawing at West Ham.
The table would have made pretty grim reading if those scores had remained.
Instead McGhee returns to Molineux for the second of four games in nine days with his team enjoying a comforting cushion again over the quartet below.
Rotherham are still stranded, despite a shock win at Leicester. Gillingham and Forest, losers at Upton Park, are now seven points adrift and Cardiff five after Wolves held them to a draw.
Such relatively modest margins with more than 20 games to go nevertheless count for much more at the bottom of the table than at the top.
Forest have won only four matches all season, Cardiff five and Gillingham six. McGhee acknowledged: "It's a very important win for us. It probably means Gillingham need to win three more games than us to finish above us and that is going to be difficult for them.
"It gives you confidence to see these other teams being beaten because you think to yourself why should it suddenly change for them?" Although what happens around Albion has an impact, self-help is McGhee's main motto. He mentioned in his programme notes for this proverbial six-pointer: "The chatter at Monday morning training was of other teams' results but I still try to maintain the line and convince the boys that is no way to talk.
"The reality is if we take around 50 points, perhaps a few less now, then we will still be in this division next season."
A victory achieved in improbable manner was a satisfying way to start the hectic Christmas and New Year period.
Albion came from behind to win for the first time in McGhee's reign and scored two goals for the first time since mid-September.
The identity of the first goalscorer emphasised there is no room for sentiment when you are embroiled in a relegation scrap.
Richard Carpenter, born in Kent, spent the first dozen years of his career with Gillingham. The midfielder's first start of a season delayed for him by summer knee surgery came in the 1-0 win at the Priestfield Stadium in September and he made the double possible by hauling Albion level 12 minutes from time with a strike as crisp as the weather.
Charlie Oatway's cross was headed away unconvincingly by Alan Pouton. Carpenter, too high with a good chance in the first half, rifled a low drive from 25 yards beyond Paul Gallacher, Gillingham's excellent keeper on loan from Norwich.
Carpenter, even once fit, has been an irregular starter so far this term. That promises to change now that Darren Currie has gone to Ipswich and McGhee is looking to Carpenter to become an influential figure again after ending a drought stretching back to the playoff semi-final first leg at Swindon.
"Hopefully that will fire him to have a great second half to the season," McGhee said.
"He is still working to get up to the heights that I know he is capable of."
Adam Virgo reached heights few would have imagined he was capable of as a centre forward in the early stages of his conversion from a defender. There has been something of a lull, both in his effectiveness and goalscoring, but his two-month famine came to an end with two minutes left.
Kerry Mayo, preferred to Dan Harding at leftback, delivered a long throw which Mark McCammon helped on for Virgo to slot his sixth and most valuable goal of the campaign from close range.
Gillingham could not complain about the justice of the outcome.
Gallacher was by far the busier keeper, saving at the feet of McCammon and a shot from Virgo early on. He also made a fine stop from a downward header by the on-loan McCammon who, together with Oatway, scuffed wide another opportunity to open his account.
Crofts' 34th-minute goal against the run of play, although well-taken, was something of a present for the Welsh junior international from Paul Reid and Michel Kuipers.
Reid, expecting Kuipers to collect Nicky Southall's hanging cross, was caught ball watching as Crofts stole in unchallenged to head into the roof of the net from eight yards.
Albion are giving away goals at the moment, rather than making opponents work hard for them. That is a slight cause for concern, which would have been felt more keenly had the unmarked Crofts connected better with another header a minute after scoring. Stan Ternent, suffering his second defeat in three games since taking charge of Gillingham, claimed afterwards the match should never have been played.
Referee Lee Probert and his assessor Paul Alcock were sceptical about both goalmouths and had them watered and forked right up until the kickoff.
McGhee was as perplexed as most people that the pitch had not been covered, given the widely predicted conditions. Albion had monitored at regular intervals a weather forecast presumably provided by Michael Fish!
However, McGhee added: "We have got to start believing in our ability. We know about the character and spirit but that is not enough.
"Some of them just don't realise what good players they are."
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