The Gunners currently sit second in their Champions League group that also contain Borussia Dortmund, Anderlecht and Galatasaray.
With all being well in their remaining four games Arsene Wenger's side should progress into the last-16 with little difficulty, but if they are to really challenge for the crown of Europe's best team then they need to stop getting players sent off.
In the last seven games Arsenal have played against European competition they have had five players sent off.
From the four Champions League fixtures they have played in this season, including qualifiers, Arsenal have received three reds.
Polish goalkeeper was given his marching orders last night against Galatasaray, Ramsey was sent off in the second leg against Benfica and Debuchy was given an early bath in the first leg.
The two that came in the latter stages of the tournament last season were in the 2-0 group stage defeat to Napoli, and the first leg of their last-16 tie with Bayern Munich.
In the majority of the games in which they have gone a man down they have struggled and the final results show this. They were already thrashing Galatasary 4-0 when Szczesny hauled down Yilmaz, so that's a bit of a different scenario.
However they weren't convincing in either of the qualifying legs against Benfica, drawing the first 0-0 in Portugal and only winning the return leg 1-0.
The Gunners were also beaten 2-0 by both Napoli and Bayern, after seeing Arteta and Szczesny given their marching orders in their respective matches.
It is a problem the Arsenal boss needs to address soon. Having men sent off in the group stage isn't such a huge problem because the tables aren't decided by one or two matches.
The problem lies between the last-16 and the final; having a man sent off between these to stages can really cost a team dearly.
Wenger must address this problem and nip it in the bud now before the Gunners progress any further in the tournament.