Andrew Robertson admitted Liverpool were “nowhere near good enough” as they slumped to a 3-1 Premier League defeat at Brentford on Monday. Jurgen Klopp's side were a shambles in the first half at the Community Stadium as they conceded two goals — through Ibrahima Konate's own goal and Yoane Wissa — and saw another two disallowed for offside. Three half-time substitutions by Reds' manager Klopp, including captain Virgil van Dijk, gave Liverpool a much-needed lift and Alex Oxlade-Chamberlain headed his team back into the game in the 50th minute. But Brentford showed tremendous fight, backed up by a raucous home support, and six minutes from time man-of-the-match Bryan Mbeumo out-muscled Konate before calmly finishing to seal the three points. Brentford are now unbeaten in six games and climb to seventh, one place and two points behind Liverpool, who have a game in hand on the London club. “First half [was] nowhere near good enough. Everything we worked on we never done,” said left-back Robertson, who made a big difference to Liverpool after coming on as part of the triple half-time change. “They were first to second balls, we gave away cheap set-pieces, we knew they were a good set-piece team, really good at corners. We have to be so much more aggressive than they are when the ball comes into the box and we didn’t do that.” Despite missing top-scorer Ivan Toney, Liverpool went the same way as Manchester United and Manchester City this season by falling to defeat against Thomas Frank's team. “I can’t say that they’re surprising me, the players, but they keep impressing me massively,” said Bees manager Frank. “Obviously it’s a fantastic result for us in many ways. “We need more than 11 players and I’m so pleased that Wissa came in and he scored. He played fantastic and we knew that he was good to run in behind.” Struggling Liverpool striker Darwin Nunez missed a glorious early chance to put his team in front after he was slipped in behind the defence by Mohamed Salah. The Uruguayan round Bees goalkeeper David Raya and rolled it towards goal, only for Ben Mee to arrive in the nick of time to slide in and block on the line. At the other end, Wissa sent Mbeumo clean through on goal but the Cameroon frontman’s shot was well saved by Alisson. However, from the resulting corner, the hosts took the lead when the ball ricocheted off the knee of France World Cup finalist Konate and squirmed past Alisson. Mbeumo’s corners continued to cause the visitors problems and Wissa put two of them into the net only for both goals to be chalked off. However, the DR Congo winger made it third time lucky four minutes before half-time when he buried a superb header from Mathias Jensen’s cross. Alisson got a hand to the ball and scooped it out but referee Stuart Attwell’s watch buzzed to confirm Wissa finally had his goal. Klopp had seen enough of the shambles at the back and replaced Van Dijk with Joel Matip as one of three half-time changes. The luckless Nunez did manage to find the net shortly after the restart after breaking through one-on-one with Raya, only for VAR to pull him up for offside. Moments later, Liverpool made one count, Oxlade-Chamberlain glancing in a header from Trent Alexander-Arnold’s tempting cross. The Reds pressed for an equaliser but Raya did well to keep out a Fabinho shot and Konate headed wide. And Brentford ended their hopes six minutes from time after Mbeumo brushed off a feeble challenge by Konate and tucked away the third. “The problem is we played here last year, it was 3-3, it was a wild game,” said Klopp. “Tonight it was the same, it was as wild as that. If you compare these two games it’s not too much different. “We should’ve scored twice before they have the first corner. When we were direct, we were always very dangerous. In the end it became the game they wanted.”