I find hard to believe that Arsenal will lose points with Brentford , but I do see this as a very tough and challenging game for Arsenal just because Brentford are having an exceptional run and season so far that a defeat with Arsenal won't leave much sorrow for the fans. Besides this , Arsenal are mentally prepared to give their best in order to win EPL title this season even if what you said about their latest performance is kinda true because they didn't perform at all at a higher level but it was expected after such a godlike run. 
The same way I find it very hard to believe that they lost against Everton; having such a chance was belittling, but since they played with every Sense of pride, they lost to a team on the relegations?? Ohh C'monnnn...Now they've been set to face Brentford on the 7th position, that hasn't much decent wins, -- maybe apart from beating Southampton to a pulp on their last match... Well, let's see what it yeilds....but I know for sure that Arsenal is on huge pressure this time around.
Edit: arsenal is topping the table with only 5 GD points, so I think they'll do everything to avoid losing again.
Sandra 🧑🦰
They are so prepared for this game Arteta wouldn't want to miss out on this game again the following week would be a meeting with City at home to if they fail to win today they still have all it takes to loss the next. Meanwhile City are at the verge of points deduction once the case been concluded they will be be going down to eight points or nine in the premier league table