Graham Potter:
The Chelsea boss endured a horror return to Brighton and saw his team beaten by the time the half-time whistle sounded at the Amex.
Brighton were three goals to the good by the break in a commanding first-half performance and it’s no exaggeration to say the Seagulls could have had a few more as they carved Chelsea open at will.
Brighton's intensity and desire was simply too much for their opponents, who surrendered possession meekly and slipped to a first league defeat under their new coach.
Potter did make changes at the break, which brought about some improvement, but it was a case of too little too late by the Chelsea boss.
Not an afternoon he'll remember fondly.
Christian Pulisic:
Potter named the USMNT star in his line-up for the second match in a row but he's likely to be heading back to the bench after another underwhelming performance.
Pulisic really ought to have scored in the first half when Robert Sanchez parried Conor Gallagher's effort into his path but he couldn't even find the target, let alone work the goalkeeper. It was a terrible miss.
The rest of the game largely passed Pulisic by and it was no surprise to see him hooked in the second half as Potter searched desperately for a way back into the match.
Chelsea's back three:
Chelsea reverted to a back three but the decision backfired spectacularly as the Seagulls scored four and will feel they could have had a few more too.
The visitors looked defensively frail throughout the 90 minutes as De Zerbi's attacking, aggressive approach paid off and exposed Chelsea's defensive limitations.
Cucurella and Trevoh Chalobah both found it tough going on either side of Thiago Silva and received little help from Sterling and Pulisic as the two wing-backs.
Potter may decide to rethink his formation now, particularly with key games against Arsenal, Manchester City, and Newcastle to come before the 2022 World Cup.