Brentford pulled off their latest Premier League shock by beating Liverpool 3-1 at home on Monday, bringing Juergen Klopp's side's four-game winning streak to an end and rattling their top-four ambitions.
Liverpool's first defeat in five league matches left them in sixth place in the standings on 28 points after 17 games, four behind fourth-placed Manchester United who can increase the gap to seven points when they host Bournemouth on Tuesday.
Liverpool defender Ibrahima Konate knocked the ball into his own net in the 19th minute while Yoane Wissa doubled Brentford's advantage before halftime after his side had two goals disallowed following VAR reviews in a frantic opening 45 minutes.
Darwin Nunez struck for Liverpool early in the second half but his goal was then ruled out for offside.
Alex Oxlade-Chamberlain did give Liverpool hope when he headed in a fizzing cross from Trent Alexander Arnold soon after but Bryan Mbeumo clinched all three points for Brentford in the 84th minute.
The victory added to a shock 4-0 win at home to Manchester United in August and a 2-1 triumph at champions Manchester City in November, taking Brentford up to seventh in the standings on 26 points after 18 games.
Brentford were missing their top scorer Ivan Toney through injury but made their more illustrious opponents suffer with their intense game plan and also capitalized on some slack defending from the visitors.
“Ivan is such a key player for us and has been fantastic in many ways," said Brentford coach Thomas Frank. “If you ask me if I want to play him I'll say ‘'Yes, of course'. But we need more than 11 players and I’m so pleased that Wissa came in and scored."
Liverpool could have taken the lead in the fifth minute when Nunez saw his shot cleared off the line by Ben Mee while Mbeumo was then denied down the other end by Liverpool goalkeeper Alisson.
Brentford took the lead with the help of some good fortune, Konate connecting with a corner with his knee and sending the ball trickling into his own net.
Wissa thought he had doubled Brentford's advantage when he bundled the ball into the net but the effort was ruled out as the forward had left the pitch.
There was yet more frustration for Brentford when they had a second goal disallowed after Mee deflected a Wissa shot into the net.
But just 13 seconds later, Wissa made it third time lucky by heading the ball past Alisson and over the line.
Liverpool coach Klopp took drastic action at halftime, taking off Virgil van Dijk, Harvey Elliott and Konstantinos Tsimikas. The team improved in the second half and after Oxlade-Chamberlain had reduced the deficit they hemmed Brentford into their own half in search of an equalizer.
But Brentford hit them on the counter attack, Christian Norgaard launching a long diagonal ball towards Mbeumo, who outmuscled Konate before slotting into the net.
Klopp said that goal should have been ruled out for a foul but did not hold back from criticizing his team.
"We conceded the first goal in a moment when we should already have been 2-0 up, with misses from Darwin and Kostas (Tsimikas) pretty much alone in front of the goal," said the Liverpool coach.
"But we get away with a goal from an offside position and then they score immediately and we are not there, so that’s a massive point for criticism."