Liverpool missed the chance to edge closer to the Premier League 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.
A triple half-time change from a visibly frustrated Reds’ manager Jurgen Klopp, including replacing captain Virgil van Dijk, had the desired effect and Liverpool pulled one back through Alex Oxlade-Chamberlain within five minutes of the restart.
At that stage the momentum seemed to be with Liverpool, but Brentford weathered the storm.
With six minutes left, Bryan Mbeumo sealed an impressive success, brushing off Konate in pursuit of a long ball before slotting home.
Brentford are now unbeaten in six games – their best run in the top-flight for more than 80 years – and climb to seventh.
Liverpool, who would have been a point off fourth with a win, stay sixth and two points clear of the Bees.