Liverpool head coach Jurgen Klopp expressed his displeasure at the officials following his side's 3-1 defeat at the Gtech Community Stadium.

Brentford produced an outstanding first-half performance to take a two-goal lead into the break, despite Yoane Wissa having two strikes disallowed for offside, thanks to an Ibrahima Konate own goal and a Wissa header.   

Darwin Nunez thought he pulled one back minutes after the break but it was disallowed for offside as well. Moments later, Alex Oxlade-Chamberlain did so with a header from a delightful in-swinging Trent Alexander-Arnold cross. 

Liverpool were the team on top for the second half, with Thomas Frank's side defending resolutely to earn the three points, which were secured after Bryan Mbeumo took advantage of Konate's failure to deal with Christian Norgaard's pass in the 84th minute and, in doing so, finalising Brentford's first win over Liverpool since 1938. 

Mbeumo's goal should not have counted

Despite his side's below-par performance this evening, it was Mbeumo's game-sealing goal that cause the German coach the most frustration. 

As the 23-year-old went to deal with the ball, he received a nudge and was sent off-balance by the Brentford forward. It was deemed legal and Klopp feels that the officials are hiding behind the 'clear and obvious' with these kinds of decisions. 

"Yes, I wish we would've done better," Klopp reflected in a post-match interview with Sky Sports. 

"I think on the third goal, I have no clue, it can only [be a] foul in that situation. When in a full sprint and [you] get a push in the back, you lose control and you go down.

The 55-year-old feels that if the goal had been disallowed, his side would have continued on the ascendency and possibly produced an impressive comeback. However, the goal killed the Reds' momentum. 

"These are the situations he [Stuart Atwell] has to explain, if somebody would ask him. 

"Again, we lose 2-1 because we don't score another goal, but, of course, it changes again ten minutes before the end, 16 with extra-time, the mindset and the mood. So with the 2-1 I wish to have seen the last 15-20 minutes, but was it was not given tonight and we have to accept that." 

Dismay over Brentford's manipulation of the laws 

Brentford continued their threat from set-pieces and throw-ins and, like a number of teams this season, Liverpool struggled. Klopp expressed that Brentford stretch the laws of the game and that there is a reason why they are so successful in offensive set-pieces but struggle in defence.

"There's a reason they are so successful with offensive set-pieces and still concede a lot of goals from defensive set-pieces, because there you can't do the same stuff because in your box it would be a penalty. That's why they do well, but there are rules and that is what you have to see."

Klopp later emphasised that in a meeting with the PGMOL at the start of the season, managers were told that referee would be clamping down on infractions in the area. 

"The behaviour in the box the refs will whistle, but unfortunately they don't do it. Do I expect it? I don't expect every little thing in our favour. 

"A foul's a foul, holding is holding, pushing is pushing, and there are a few things you are allowed, some things are not allowed. If the ref would see them, then they'll whistle it; if they don't see then they can't whistle it, it's how it is." 

No Toney, no problem 

Ivan Toney has been Brentford's talismanic figure this season, with 15 goal contributions in 16 Premier League appearances, including a goal and an assist in the 2-0 win over West Ham United on Friday, but an awkward landing in the closing stages of that match ruled him out of contention to face Liverpool. 

Wissa was elected in his absence and, watching on behind the bench, Brentford's top scorer witnessed the 26-year-old produce an excellent performance alongside Mbeumo, causing immense havoc on the break and getting a goal apiece. 

Even in the absence of such an important player against tough opposition, Frank never lost faith in his side. 

"Ivan is such a key player for us and he's been fantastic in many ways, and if you asked me if I want to play him, yes, of course I want to, but we need more than 11 players," he told Sky Sports. 

"I am so pleased Wissa came in and he scored, and I think he is our second top scorer in the Premier League over the last two seasons, and he played fantastic.

"We knew that he is good to run in behind and also that position he found in the box for the second goal is something he is really good at." 

He was then asked if the game plan changed without Toney at his disposal. 

"No," he responded bluntly. 

"We still knew that was to play [in] behind. You can play that little bit more direct, with Ivan up there makes it a little bit easier, but the approach was the same." 

Brentford a little fortunate but Frank is very impressed with their performance

The Bees have proven to be tough opposition for the notorious 'big six' this season, previously defeating Manchester City and Manchester United while drawing with Tottenham Hotspur and Chelsea. Even with the frequent occurrence, Frank continues to be impressed by his team. 

"The players keep impressing me, massively. It is a fantastic result for us, in many, many ways, but to do what we are capable to do here against Liverpool, it's very impressive." 

Brentford drew 3-3 in a thrilling previous meeting in west London last season and Frank was asked whether there was much of a change in the approach for this fixture.

"No. Not too much difference. 

"Because the whole game was a fantastic game, but I felt it was a bit too open and [with] the transitions and the pace Liverpool had, we had to be a bit more aware of that. 

"We knew Nunez wanted to go behind and it was close to costing us twice: one a great block on the line from Ben [Mee] and then the last one, yes it was offside, I love Ethan Pinnock but I don't think he played on the offside. I think we were a bit lucky there. So we either went all the way high and be aggressive or very low in the block."

Brentford's victory momentarily lifts them into seventh in the table, ahead of west London rivals Fulham and Chelsea as well as two points behind Liverpool, with the rest of the round's fixtures yet to be played.