Bournemouth ended Liverpool's 13-game unbeaten run as Amine Adli's 95th-minute strike secured a thrilling 3-2 win for the Cherries on Saturday.
Goals from Evanilson and Alex Jimenez put the home side in a commanding position, but Liverpool hit back through Virgil van Dijk and Dominik Szoboszlai to level.
However, Bournemouth won for just the second time in 15 matches after Adli fired in with virtually the last kick of the game.
Defeat will intensify the scrutiny on Liverpool boss Arne Slot, with the Reds likely to fall outside of the Premier League's top four after Sunday's fixtures.
Slot, who guided Liverpool to Premier League glory last season, had steadied the ship after a run of nine defeats in 12 games earlier in the campaign.
But the Dutchman has attracted criticism for Liverpool's uninspiring performances, even during their unbeaten run, and they are now winless in five league games.
The Reds put in a commanding performance to beat Marseille 3-0 and close in on the Champions League last 16 in midweek.
But they again struggled when faced with the rigours of breaking down a Premier League defence after gifting the Cherries a 2-0 lead.
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The visitors dominated the ball throughout, but were made to pay for two defensive lapses in seven first-half minutes.
Van Dijk was too casual as he tried to flick Marcos Senesi's ball over the top behind for a corner and Alex Scott pounced to cross for Evanilson to hammer home.
In trying to prevent the goal, Joe Gomez picked up an injury to further deplete Liverpool's already threadbare options at centre-back.
The visitors were down to 10 men as Wataru Endo waited to replace Gomez when Bournemouth doubled their lead.
Milos Kerkez was caught sleeping on his return to the Vitality Stadium to allow Jimenez to sneak in behind and slot in his first Bournemouth goal.
Van Dijk atoned for his previous error to begin the Liverpool fightback when he headed in Szoboszlai's corner.
REWARD FOR POSITIVITY
Andy Robertson replaced Kerkez at halftime despite being linked with a move to Tottenham before the transfer window closes in just over a week's time.
Liverpool had little to show for their domination of the ball in the second period until Szoboszlai's strike sparked a wild finale.
The Hungarian slotted a free-kick under the Marseille wall on Wednesday and this time used a flick from Cody Gakpo to work an angle to blast into the far corner.
Almost straight from kick-off, Liverpool needed Alisson Becker to produce a brilliant save from Ryan Christie to prevent Bournemouth from retaking the lead.
Evanilson then wasted a glorious chance to win the game when the Brazilian slotted wide with just Alisson to beat.
Bournemouth could also have lost it when goalkeeper Djordje Petrovic made a fine save to prevent Florian Wirtz from finding the bottom corner.
But Andoni Iraola's men were rewarded for going for the win when Adli smashed in from a narrow angle after Liverpool failed to clear a long throw.
Victory lifts Bournemouth up to 13th and 10 points clear of the relegation zone.