Although the afternoon began well for Chelsea, scoring their first goal in four games, the match was turned on its head by Brighton's creativity in attack and their desire to take full advantage of this lacklustre Chelsea side, who will only be focused on their UEFA Champions League tie with Real Madrid.
Frank Lampard made several changes to his team in preparation for that quarter-final, but it was the same old story for Chelsea this season. Here's four things we learnt from their battering against Brighton:
Mitoma's Magic:
Brighton forward Kaoru Mitoma was their stand out performer on the afternoon, just as he has been throughout recent weeks.
The Japanese international gave stand in right-back Trevor Chalobah a torrid time, with Brighton's most positive plays coming from their left-hand side. Chalobah picked up a booking and was ultimately replaced by a more obvious right-sided player in the second-half for Reece James, who did not look like a player in the flight of full fitness.
Mitoma was the danger man throughout the match for the visitors, and Kepa Arrizabalaga kept Chelsea in the game with some exceptional saves, particularly in the first half, to deny Mitoma the opportunity to get on the scoresheet to add to his seven goals and four assists.
Seagulls' 26 Shots:
In fact, Kepa deserves more credit than the rest of his teammates on this occasion, as he kept the scoreline respectable for Chelsea and Lampard.
Brighton managed to rack up 26 shots during their game at Stamford Bridge, with Chelsea only managing eight. With ten of Brighton's shots on target, it was the home side's keeper who was the busiest, something that spread disgruntlement amongst the home supporters, as it always seemed to be a matter of time before Chelsea's opening goal was cancelled out.
The goal that won the game came from 19-year-old Julio Enciso, who struck an incredible shot from outside of the penalty area to put the game past Chelsea, and ensure that the Londoners went a sixth game without a win.
Muydryk's Milestone:
Mykhailo Mudryk, who signed for Chelsea in January had his best game yet in a blue shirt, despite the overall disappointing result. For the first time, the Ukrainian completed 90 minutes, and for the second time in his short Chelsea career, he registered an assist, setting up Conor Gallagher for the opening goal.
Mudryk's pace was a constant threat and looked to be the only way to test for any fragility in Brighton's back line, drawing a yellow card from Joel Veltman in the opening minutes of the first half with his acceleration.
Although some of his performances still exhibit a rawness of talent that needs to be refined, Mudryk offers something different to Raheem Sterling or Christian Pulisic, the players who joined him in the starting front three, with his sheer ability to turn opposition players on their heels, and take them on.
In the closing stages of the game, with Chelsea about to suffer another defeat, Mudryk fired a ferocious shot at Robert Sanchez in the Brighton goal, which went narrowly over the crossbar, but roused belief in the talents of the £88 million pound man.
70th Minute Exodus:
When Brighton's second goal went it, many Chelsea supporters took their cue to leave Stamford Bridge. Watching a side that had only managed one goal in five games, it seemed wholly unlikely that Chelsea were going to have any answer to retaliate in the game.
Despite Lampard bringing on many of the players that he was seemingly trying to rest for the mid-week clash against Real Madrid, he could not turn the tide. Joao Felix was unable to make any impact when he was introduced, and Moroccan Hakim Ziyech was also ineffective.
Though the home crowd faithfully sang Lampard's name at times, it was not a performance to put any faith into Chelsea supporters that their season will end in anything but colossal disappointment. Lampard does not look like a man with the answers and owner Todd Boehly, who was in the crowd, was seen remonstrating with Chelsea supporters in the stands.
It is a tough time at Stamford Bridge, and by the time that the 96 minutes were up, Chelsea supporters had already left in their droves, believing that their side have no hope of overturning a two goal deficit against the European champions in just a few days time.
