One moment of madness wrecked Albion's hopes of halting Reading's relentless surge towards the Premiership.
No, not Gary Elphick's unfortunate dismissal three minutes into the second half.
That merely confirmed the inevitable. The damage had already been done in the first half, when the Seagulls allowed the table-toppers the softest of leads.
For the best part of half-an-hour, Mark McGhee's game plan had gone according to plan.
His decision to give Elphick his debut as a third central defender alongside his close friend Adam El-Abd and Guy Butters helped stifle Reading to such an extent that they had not created a worthwhile chance.
The complexion of the match suddenly changed when Alex Frutos found himself isolated in leftback territory.
Glen Little rounded him with ease before crossing low into the sixyard box where Charlie Oatway, caught in two minds, could only turn the ball into his own net.
In that instance the Seagulls' chances of causing an upset effectively evaporated. What happened afterwards was little more than window dressing, impacting on the margin of Reading's seventh straight Championship victory rather than the result itself.
Former Albion boss Steve Coppell knew it. "As soon as I saw the way Brighton were going to play, the hardest part for me was always going to be getting the first goal," he said.
"Once we got the goal, with great individual play by Glen Little, I didn't think we were going to lose. We had the initiative then."
McGhee, entitled though he was to question the validity of Elphick's red card and Dave Kitson's penalty in the space of two minutes at the start of the second half, appreciated, too, that Seagulls pay for one mad moment the first goal was the true turning point.
"Up to when they scored, which was a poor goal from our point of view, they didn't have a kick," he said. "We didn't deal with it well.
"Reidy (Paul Reid) allowed Alex Frutos to do his job when he should have been stepping out there and we ended up losing a goal from a situation we should have dealt with quite easily."
You had to feel sorry for Elphick. He was booked just two minutes into his full debut after tangling with Kevin Doyle as the Irish striker threatened to latch onto Nicky Shorey's pass out of defence.
Several minor infringements later referee Paul Taylor decided the teenage rookie brought Kitson down as he turned away from him and two yellows became red.
The opinions of Albion's last two managers on Elphick's early bath could hardly have been more diverse. McGhee called it "ridiculously harsh", Coppell countered: "I can't see what the problem was. You can question the first booking but it was probably justified. With the second one, Kitson was through on goal if he had been allowed to stay on his feet."
A goal down and a man down, McGhee's players held their heads in disbelief when, following the free-kick arising from Elphick's exit, Kitson appeared to dive inside the area without Gary Hart making any significant contact.
Kitson gave Alan Blayney no chance of completing a hattrick of penalty saves, sending him the wrong way and Albion towards their second defeat in ten away.
The only issue then was how many Reading would win by.
They capitalised on their numerical advantage as a quality side should, Kitson nodding in from close range when Shorey's shot looped obligingly to him off Guy Butters and sub Stephen Hunt diving to head in Shorey's cross four minutes later. At least Albion scored the best goal of the six. Colin Kazim-Richards, who impressed when he came on, left Marcus Hahnemann helpless with a swerving drive from 30 yards.
It was Kitson, though, who had the final word. He completed his hat-trick deep into stoppage time with a header from Steve Sidwell's cross which Blayney got hands to but could not keep out and which had already crossed the line when Hunt made sure.
It was not a day for Albion's flair players. Seb Carole, substituted in the second half, performed as if still feeling the effects of the twisted ankle he suffered against Watford. Fellow Frenchman Frutos was similarly subdued.
Leon Knight, forraging alone up front, got little change out of Reading's miserly defence. His eventual withdrawal enabled an Elphick to still be on the pitch at the finish, Gary's younger brother Tommy getting his first taste of first team action.
Such an ultimately heavy defeat should be put into context.
Reading are, by some distance, the best side Albion have played this season and it ought not to affect the fight to stay up.
The Seagulls are very good at putting disappointments behind them quickly and moving on.
They need to because their most important match of the season so far is looming against Hull at Withdean on Friday.
The bottom four all lost on Saturday and the teams immediately above them, Plymouth and Leicester, each have a game in hand, so there is the potential for a nasty little gap developing.
Hull and Coventry have both demonstrated what a power of good a couple of wins back-to-back can do. Albion now have an opportunity to follow suit against the Tigers and QPR on Boxing Day.
The season has only reached half-time, so it is too soon to panic, but the Seagulls must start winning. If 19 points from 23 matches becomes 38 from 46 they will be two divisions apart from Reading next season.
- Albion (5-4-1): Blayney 7; Hart 6, G. Elphick 5, El-Abd 7, Butters 7, Reid 5; Carole 5, Oatway 6, Hammond 8, Frutos 5; Knight 6. Subs: Kazim-Richards 7 for Carole (withdrawn 55), Robinson for Reid (withdrawn 66), T. Elphick for Knight (withdrawn 73), Nicolas, Chaigneau.
- Reading (4-4-2): Hahnemann; Murty, Ingimarsson, Sonko, Shorey; Little, Sidwell, Harper, Convey; Kitson, Doyle. Subs: Gunnarsson for Harper (withdrawn 73), Hunt for Doyle (withdrawn 73), Oster for Little (withdrawn 79), Stack, Makin.
- Matchfacts
- - Shots on goal: Albion 4, Reading 8.
- Shots off goal: Albion 5, Reading 6.
- Corners: Albion 1, Reading 7.
- Offside: Albion 1, Reading 4.
- Free-kicks: Albion 15, Reading 11.
- Albion bookings: Hammond (26) foul, Carole (45) foul.
- Sent off: G. Elphick (2) foul and (48) foul.
- Reading booking: Shorey (43) foul.
- Albion scorer: Kazim-Richards (84).
- Reading scorers: Kitson (50) penalty, (71) and (90), Oatway (27) own goal, Hunt (76).
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article