Albion suffered their first home defeat since New Year's Day as Southampton put their early season problems behind them.
James Beattie finished a goal famine for the Saints spanning five hours and 15 minutes when he struck just before the break.
That proved to be the turning point, Anders Svensson embellishing the Premiership strugglers' first win of the season with two late solo efforts.
To put the result into perspective, Southampton spent around four times as much on Svensson as it has cost Micky Adams to assemble his entire side.
The Swedish international midfielder set the Saints back £700,000 from Elfsborg in the summer, a snip in Premiership terms yet far more than Albion have ever forked out for any player.
The Saints' starting line-up last night was put together for a total sum well in excess of £8 million, so the outcome should not have surprised even the most ardent Albion fan.
Yes, Southampton arrived at Withdean without a point or a goal and the Seagulls were on an 11-match winning streak at their temporary home.
But those defeats for Micky Adams' old club were against Leeds, Chelsea and Spurs, the victories for his current one against the likes of Mansfield, Macclesfield and Blackpool.
Adams' assessment was impossible to argue with. "I've no complaints about the result," he said. "It was always going to be a difficult game, but I was pleased.
"The things we could match Southampton for - workrate, effort and commitment -
we did, but the sort of finishing power they showed costs so much and we haven't got that."
Albion, in fact, matched the Saints for 44 minutes. One of the few disappointments was the rather sloppy manner in which they fell behind.
Svensson's cross from the left took a slight deflection on its way towards the danger zone.
Matt Wicks, stretching in an attempt to clear, could only knock the ball up for Beattie to swivel and volley into the roof of the net.
It was Southampton's first goal since Adams'
chum Matt Le Tissier ended the last ever League game at the Dell against Arsenal at the end of last season with a trademark strike.
Albion did not show quite the same conviction in the second half and Svensson killed them off in clinical fashion.
He put the tie out of their reach with 19 minutes left, running from just inside the Seagulls' half before cutting inside Wicks to score with a precise right-foot shot from 12 yards.
Svensson struck again five minutes from time. He completed a diagonal run, which took him across Wicks and substitute Kerry Mayo, with another sweet right-foot finish from the edge of the area.
Wicks, making his first appearance of the season in place of the hamstrung Danny Cullip, was unfortunate to be involved to some degree in all three goals.
He was thrown in at the deep end, bearing in mind how little first team football he has played in the last six months because of injuries, and Adams said: "Wicksy stood in abley."
Undoubtedly the star of the show though for the Seagulls was Michel Kuipers.
The big Dutchman kept the margin of defeat respectable with a series of fine saves in both halves.
He made three eye-catching stops in as many minutes early on from a close range shot by the unmarked Beattie, a Dean Richards header following a corner and an angled drive from 20 yards by Jo Tessem.
The pattern continued in the second period as Kuipers blocked with his feet to foil Scott McDonald, an 18-year-old Australian making his senior debut up front for Southampton.
The former marine also denied a Kevin Davies snapshot from just inside the box and in the dying stages dived to divert a fierce effort from Rory Delap, the visitors'
record £4 million buy from Derby.
It was far from being all one-way traffic.
Albion enjoyed plenty of possession and passed the ball well at times without ever testing Kuipers' counterpart Paul Jones.
They could point to a couple of early decisions, inevitably involving Bobby Zamora, which would have changed the course of the contest.
In the third minute Paul Watson, rejected by Southampton as a schoolboy, caught their defence napping with a free-kick which an alert Zamora tucked away.
It was ruled out by a marginal offside decision from the linesman and Zamora also had claims for a penalty rejected by referee Mick Fletcher when Tessem appeared to pull him down.
Kuipers, who had only previously conceded three goals in the last match of last season at Shrewsbury, remained justifiably upbeat.
"We are not down at all," he declared.
"This game was a bonus for us and we gave a good performance.
"We were a bit unlucky with the first goal.
It was bad timing and in the second half we tried to push up more, which gave them more space."
Southampton boss Stuart Gray said: "I'd rather we had won three points, but it's a nice relief to get that first goal and a good win.
"That is why I bought Anders. I knew he had that in him and they were two special goals. We now need to convert cup goals into Premier League goals and concentrate on Bolton on Saturday."
For Albion it's back to the bread and butter and a Friday night trek to Wrexham.
Unattractive as that may seem, they have the perfect incentive of knowing a win will take them to the top of the Second Division table for at least a few hours.
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