Porto will try defensive tactics because they already have the advantage in the first leg. Porto can play very well with their defense. This can be seen from the first leg. But Arsenal played as host in this match. That will give them additional morale and motivation to win the match. Even though it was difficult to win the match against Brentford, I think the match against Porto will be different because Arteta will really prepare a strategy and Arsenal will go all out to win the match. I predict Arsenal will progress to the next round.
Having a narrow lead of one goal in the first leg is still not necessarily safe for FC Porto in the second leg which they will play tomorrow. Because Arsenal is also a quite dangerous team when playing in the Champions League with the motivation of being the host, FC Porto still has to try to score a goal in the second leg even though they also have to make a fairly good defensive strategy because if the lead is still very small, of course FC Porto themselves must be aware that they still need to fight hard at home to Arsenal.
The only thing that can help Porto and make this team to have better results and not lose the game against Arsenal is a miracle because we know Arsenal is currently on fire and they had perfect results in the Premier League and other games we saw from this team which can be the reason to say Arsenal can easily beat Porto.
On the other hand, Arsenal's attacking power has been awesome so far and since they need to lose the first leg with a 1-0 result and they need to score two goals to make sure about this match, I predict to see a nice game between these two teams while Arsenal is going to have attacking style during this game from the start of the match.