Most likely Porto will use a defensive strategy and target a draw at the Emirates, Arsenal will have difficulty beating Porto even though the goal margin is only 1-0. On paper Arsenal chances were very good, but when they dominated the match and created chances, no one could convert them into goals. Porto would really benefit if Arsenal still played with the same style, they also wanted to qualify for the quarter finals and Arsenal failed to anticipate their style of play.
Arteta seemed very disappointed with the results his team got. It was reported that Arteta criticized his squad and Porto playing style as a result of this defeat. Dominating the match will not always result in victory, Arteta had to change his strategy in the second round. There is no point in criticizing Porto playing style, it will not change the situation at all, the most important thing going forward is how to turn things around. Arsenal chance of winning at the Emirates is quite big, but Porto cannot be underestimated a second time.
Yes, you are right, it is possible that Porto will carry out a strategy like what you said and I also said that before, I admit that Porto's defense is very strong so that Arsenal are completely unable to create opportunities, but this is likely because Arsenal's players cannot shoot on target so they don't was able to break into Porto's goal, while Porto himself shot at goal twice and 1 of them resulted in a goal in the last minute and that was of course very painful for Arsenal because who would have thought that Arsenal would try to hold a draw in the first leg so that in the second leg Arsenal would beat Porto easily but unfortunately Arsenal conceded a goal.
Of course, any coach would be disappointed if they saw their club lose, especially in a big competition like this, even all Arsenal fans would also feel the same disappointment and even many bettors would lose because of course there are many who favor Arsenal, but what is called a surprise is true. we can't predict it because Porto also cannot be underestimated, he has prepared himself before meeting on the field and this really makes him happy because he was able to beat Arsenal in the first leg and will make a defensive strategy in the future second leg if Arsenal uses a less powerful attack strategy.