This could have been much, much worse for Chelsea and Frank Lampard on his return to the Stamford Bridge dugout.
It was already something of a role reversal before kick-off, with Brighton pushing for the European places and Chelsea down in mid-table - but few could have predicted the action would be so true to form.
Brighton dominated a heavily-rotated Blues side from the first whistle, and while it could have been 4, 5 or 6-1 by full-time, it was ultimately kept down to 2-1 courtesy of a rocket from Seagulls substitute Julio Enciso.
Alexis Mac Allister went close twice and Evan Ferguson smashed the crossbar inside 15 minutes, but the hosts snatched the lead against the run of play when Conor Gallagher's strike took a wicked deflection and looped over Robert Sanchez.
Not to be deterred, Brighton continued their onslaught after falling behind, with both Kaoru Mitoma and Ferguson drawing excellent saves from Kepa Arrizabalaga before Chelsea's brief resistance was broken by a Danny Welbeck header.
Although Christian Pulisic hit the post and Chelsea were more competitive in the second period, there was an air of inevitability about the result. Sure enough, with 20 minutes to go, Enciso took aim from fully 25 yards and crashed home a wonderful winner.
That's three defeats in as many games for Chelsea since Lampard's return, with the small matter of Real Madrid on Tuesday.
GOAL breaks down the winners & losers from Stamford Bridge...