Can't guess how Arsenal will play later --- whether to play defense or more to attack like in the first leg, but if Arsenal's game is suppressed then the possibility of Arteta's strategy could be defensive all the time, because Real Madrid's way to win will be very wild to continue to attack Arsenal's defense.
I think Arsenal will play defensively. But Arsenal is not a team that plays completely defensively. Arsenal players are capable of counter-attacking quickly. So even if Arsenal plays defensively, they have the ability to score against Real Madrid.
I say this because we saw Arsenal's performance in the round of 16 match. Arsenal won the first leg match 7-1 against PSV. Arsenal players did not take much pressure in the second leg match. Arsenal drew the second leg match 2-2. Maybe Arteta will want to apply the same strategy in this match.