In their first meeting Arsenal won Brentford at Gtech Community Stadium by 0 -3 and now they will be meeting at the Emirates Stadium. If Brentford could not resist Arsenal's attack in the first leg then they will do little or nothing to resist them from getting more points in their second game. The previous match where Arsenal lost to Everton was a game of luck for Everton which the revenge will be taken on Brentford. Brentford might have good defensive record but it can't be used against Arsenal.
Brentford will be losing again to the arsenal. I think that we can just try to realize the fact that if the gap is too big for brentford to force arsenal to draw or even defeat it. I don't even think brentford will be able to make revenge against arsenal. Arsenal itself is always playing so well in any match. Arsenal was not lucky enough in the match against fulham. Brentford is always having bad results against arsenal. The last meet with arsenal has proven arsenal can destroy brentford easily. I don't expect something big like being draw with arsenal.
The possibility will always there but arsenal will able to defeat brentford easily with same scores or even more maybe.