After putting on the best show of the Graham Potter era to see off Red Bull Salzburg in midweek, Chelsea swiftly followed it up with the worst as they were absolutely trounced by his former employers, Brighton.
Chelsea have taken the Seagulls' manager, assistant, goalkeeper coach, recruitment analyst, first-team coach and left centre-back, and they're soon to add Brighton's head of recruitment to their ranks as well, but they still looked light years behind here as they fell to a 4-1 defeat.
With Potter's nine-game unbeaten run now over, questions will be asked of just what went wrong, and the manager must look at himself for the first answer.
Admittedly backed into a tricky spot following Reece James' injury - the latest in a long line of defensive casualties - Potter opted to stick with the wing-back duo of Raheem Sterling and Christian Pulisic for this one. The pair had done well against Salzburg but were eaten alive by a Brighton side who have already proven themselves capable of scaring the bigger teams.
Neither Sterling nor Pulisic flashed any form of defensive awareness about them. They were set up in a system which was supposed to maximise their strengths and hide their weaknesses, but it did the exact opposite.
The ease with which Pervis Estupinan and Solly March went flying down either wing in the first half was terrifying and somewhat predictable. The attacking wing-backs were rarely anywhere to be seen, leaving Chelsea's three centre-backs to defend from themselves.
It's a decision which Potter got wrong, but perhaps more curiously, it's one with which he persisted for the entire first half.
Just one week ago, as Chelsea were being picked apart by Manchester United, Potter made the bold decision to withdraw Marc Cucurella in the first half in favour of adding another midfielder - a move which dragged Chelsea back into the game and nearly inspired a victory.
There was no such boldness here as Potter watched Chelsea's wing-backs disappear time and time again, and the decision to wait until half-time to adjust the shape proved costly as the damage had already been done.
The boss is by no means solely responsible - Thiago Silva gave possession away twice inside five minutes, the second of which led to the opening goal - but his desire to think outside the box proved costly as Chelsea were meticulously picked apart by a Brighton side who were still looking for their first win under Roberto De Zerbi.
An awful, awful day at the office for Chelsea, and one from which Potter must learn quickly.