Brentford manager Thomas Frank, speaking to BBC Sport, said: "I think it's important to look at what we can affect and analyse and that's our performance. I think we performed very well up here, it takes a lot of character to perform here. We performed and tried to win. I think it was a very even game.
"I think we were very close and we could have won it. Unfortunately it was decided by a decision that had nothing to do with the two teams, just the ref. But in terms of character, willpower, the way we pressed and played, we could have won this game.
"I don't think it's a penalty. We got trolled in a similar situation a some weeks ago against Tottenham when Kevin Schade was through, clear contact with the keeper took him out but apparently he [the keeper] pulled out before. And they also talked about a situation between Arsenal and Manchester City but that was penalty awarded.
"But going forward these should not be penalties. We have a keeper clearly pulling out and a player cleverly letting his leg hang there. It's not a penalty.
"If the assistant didn't take the decision, it should 100% be humans making the decisions like that, then I'm convinced that VAR would not have overturned the decision, so I think that's a problem.
"But because it's not clear and obvious, it's too tight. Now we will have a situation where Howard Webb will come out and apologise about the situation and say 'we're sorry', I just think it's too many time but it can happen."