Liverpool missed the chance to reduce the gap to the Premier League's top four as Brentford punished their defensive frailties in a deserved victory at the Community Stadium.
In a desperate first half, Liverpool shipped two poor goals amid an inspired performance from the hosts.
The opener came when Ibrahima Konate deflected a corner into his own net after 19 minutes.
Liverpool were unable to deal with Brentford's set-pieces, conceding twice more from corners in the first half only for both goals to be ruled out for offside.
Moments after the second disallowed effort from Yoane Wissa, the Bees striker headed in after Liverpool had sloppily given the ball away.