Blues easily contained by Championship opposition in final pre-season friendly ahead of next Sunday's Community Shield encounter with Manchester City
Frank Lampard opened the scoring for the Blues though efforts from Vicente, Ashley Barnes and Andrew Crofts secured a shock win for the Championship side.
The result means that Chelsea face Manchester City in next weekend's Community Shield having suffered three friendly defeats on the bounce.
With Ryan Bertrand, Daniel Sturridge, Juan Mata, Oriel Romeu and new signing Oscar still absent due to Olympic commitments, Blues boss Roberto Di Matteo still named a strong starting line-up for Chelsea's final pre-season run-out.
Petr Cech started in goal with Gary Cahill partnering John Terry in defence and Branislav Ivanovic and Ashley Cole at right and left-back. Raul Meireles, Lampard and Michael Essien formed a midfield three as Ramires and Eden Hazard flanked Fernando Torres up front.
Last season's Champions League winners took a while to grind through the gears against their Championship opponents, with a few surging Hazard runs from deep their solitary threat in the opening 15 minutes.
Chelsea eventually began to test the Seagulls' stubborn defensive resistance, though Torres was unable to convert a couple of half chances into meaningful efforts on goal.
However, it was a classy dummy from the Spanish frontman which eventually prised the hosts open after 34 minutes.
Ramires picked up a loose pass inside his own half and slotted into Torres. A clever step-over then allowed the onrushing Lampard to steer a left-footed drive underneath Tomasz Kuszczak.
The Seagulls reponse was prompt and within two minutes they were equal after Spanish winger Vicente finished off a flowing counterattack with a sweeping finish into Cech's far corner.
Moments before the interval Brighton took the lead courtesy of another swift break.
Will Buckley drove in from the right and when his effort to round Cech was snuffed out the ball fell into the path of Barnes, who rifled into the far corner.
Di Matteo made a solitary change at half-time as Mikel replaced Meireles in the middle.
In a pattern similar to the start of the first half, Chelsea's attacking patience was tested by a Brighton team keen to get men back behind the ball.
Torres failed to grasp one of few clear-cut opportunities after he volleyed high and wide when the ball fell kindly for him in the box before Vicente tested Cech's alertness with a rasping drive from distance.
Vicente continued to trouble Chelsea with his trickery and it took a sharp save from substitute goalkeeper Ross Turnbull to deny Barnes' near post header after the winger did well to create space on the byline.
Ramires slammed into Kuszczak after the ball eventually found its way to him with 20 minutes left before Lampard was blocked from close range.
Hazard went close with a speculative effort from range, though in the resulting counter Crofts doubled Brighton's lead with a clinical finish after Chelsea stood still as David Luiz went down theatrically under pressure.
The result concluded Chelsea's pre-season friendlies as Di Matteo's men look forward to their Community Shield encounter with Manchester City next Sunday.