Manchester City's backline will receive the flak - but their forwards are worthy of the blame.
When Erling Haaland fired the visitors ahead inside 23 minutes, his colleagues began to play as if this match was done.
And while Fabian Hurzeler's masterful substitutions were ultimately what swung the balance of this pulsating contest, City's misfiring attackers should also hold themselves accountable on the long, lonely journey back north.
City could have been home and dry before the half-time whistle - Haaland alone had three notable opportunities before he broke the deadlock and Savinho, evidently a majestic talent, could have taken home the match ball.
The Brazilian might be easy on the eye but his inability to convert chances is a glaring issue that Pep Guardiola needs to address on the training field.
Guardiola's alarming high defensive line was brutally exposed in the final 20 minutes when Albion striker Joao Pedro levelled before teeing up fellow sub Matt O'Riley to strike the winner but after four straight defeats in all competitions, City's attack has become just as much of a problem as their faltering and leaky defence.
We are now 11 matches into the 2024-25 Premier League and outside of powerhouse talisman Haaland (12), no City player has managed more top-flight goals than defender Josko Gvardiol and deep-lying midfielder Mateo Kovacic - both on three.
The Croatian duo have both enjoyed stellar individual seasons in their own right but those figures reflect horribly upon City's star-studded forward line - Haaland aside.
PFA Player of the Year Phil Foden - on target against Sporting on Tuesday - was bafflingly quiet and is still yet to hit the back of the net in the Premier League while Savinho, Bernardo Silva and Jack Grealish have also fired blank as we enter the November international break.
Collectively, that's zero goals from a combined 34 appearances which is borderline unacceptable.
Yes, there are mitigating circumstances - fitness struggles, injuries, rotation - however, players of such class should be delivering consistent quality in the final third, just as they did last season.
You begin to wonder whether losing Julian Alvarez to Atletico Madrid was worth the £81.5million payday given Txiki Begiristain failed to land a replacement.
City have only scored 22 Premier League goals thus far - the same number as mid-table Brentford and Tottenham - from their opening 11 matches but had already blitzed home 28 at this stage of last season.
Furthermore, they have also conceded five more goals than this time last year and their backline is looking seriously jaded ahead of crunch fixtures against Spurs and Liverpool.
Brighton's infectious energy across the park and cutting edge in the final third showed City exactly what they are currently missing.
They simply cannot rely on Haaland anymore and even he isn't totally exempt from a small slice of the blame.
Perhaps it's a sign of the times that over 650,000 Fantasy Premier League managers transferred Haaland out of their respective squads this week, making him the most-sold player in the entire game as his ownership dropped to 66 per cent.
Fantasy football may not be the greatest barometer to accurately measure decline but those statistics are incredibly damning because for the crux of Haaland's trophy-laden City career it hasn't been a case of whether he will score - it's been a case of how many he will get.
Here he was on target but in the second half, he was non-existent.
It still feels somewhat strange to be criticising a striker that has mustered 15 goals in his last 16 appearances in all competitions but it's also undoubtedly reasonable to argue that Haaland can do more.
Prior to this gut-wrenching defeat, he'd netted just one goal in his past five league games - having played against Newcastle, Fulham, Wolves, Southampton and Bournemouth - which is a poor run of form by his incredible standards.
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