Liverpool's home league record has collapsed from unbeaten in almost four years to defeats in back-to-back matches as Brighton followed Burnley in leaving Anfield with a 1-0 victory.
A fortnight ago, a 68-game run was ended by the Clarets and this was a similar story as Jurgen Klopp's side dominated possession but lacked a cutting edge.
The visitors created the best chances and the margin of victory could have been greater but Steven Alzate seized the moment with his first Premier League goal in his 28th appearance 11 minutes into the second half.
Liverpool, who have dropped points against five of the bottom six, were without goalkeeper Alisson Becker due to a non-Covid-related illness but the concerns were at the other end of the pitch.
Klopp's wait for a 100th win at Anfield continues while the Seagulls made it four league matches without conceding having taken 10 points from 12 and beaten the defending champions, Tottenham and Leeds along the way.
The victory, their first league win over Liverpool since March 1982, owed much to the organisation which Graham Potter has drilled into the Seagulls, defending en masse and then committing players to attack when they had the chance to take the game to the hosts.
It worked to a tee as there were shots on target from either side in the opening 54 minutes, a situation which would not have bothered the visitors.
The first attempt on target found the net as the impressive Dan Burn popped up at the far post to knock Pascal Gross' cross back into the danger area and Alzate ran onto it to loop a shot inside the far post, possibly via a deflection from Leandro Trossard.
That Liverpool's best chance was their first of the evening after just three minutes told its own story.
Mohamed Salah was uncharacteristically wasteful with an early chance not unlike his brilliant second at West Ham; this time it was Jordan Henderson playing the raking pass out from the back and, although the Egypt international's first touch was just as good as Sunday, he blazed over.
Burn wasted Brighton's best opening by ballooning over after Neil Maupay had sent Henderson and James Milner the wrong way only for his half-deflected shot to pick out his team-mate close to goal.
In the second half Roberto Firmino may have been brought down by Burn in the act of shooting but Nat Phillips' nudge on Lewis Dunk denied Liverpool a chance for VAR to look at their penalty claim.
Salah side-footed wide from an Alexander-Arnold cross and drilled a shot against the upper-arm of Yves Bissouma but the visitors were carving out the chances as only Henderson's last-ditch tackle denied Ben White after Caoimhin Kelleher, making only his second Premier League appearance, saved Gross' shot.
Liverpool's two new defensive signings watched from the Main Stand, Ben Davies on the bench and Ozan Kabak sat just behind not in the squad, but it was problems at the other end which were costly.
Klopp's side missed the thrust of Sadio Mane, whom the manager will hope has recovered from a muscle injury in time for the visit of Manchester City on Sunday, as they cannot afford another off-day against the league leaders.
Defeat dropped Liverpool to fourth and left them seven points behind City, who have a match in hand, while Brighton are 10 points clear of the bottom three.
