It would be an easy 90 minute win for Arsenal. Porto might have a lead over goal but they are no match to what Arsenal is now. The next game is going to be in a much different context as well. Arsenal has placed themselves as the contender for title of the premier league and the match is being hosted in Etihad stadium, the home ground of Arsenal. Arsenal will most probably have a better aggregate than porto during the gameplay and advance to the next round.
Another match on the same day Barcelona vs Napoli would be much competitive one but Barcelona would have a better play.
I agree that Arsenal will be win but it will be not an easy match for them.
In Europe competitions Porto never lost with more than 1 goal difference since Sept 2022.
I guess this match will end with 1-0 or 2-1 in 90 minutes, and the winner will be decided by a penalty shootout.
I believe that the record will end at the Emirate Stadium today. Arsenal will not allow FC Porto to score a goal first, so they will not need to struggle to win against FC Porto. Arsenal will beat FC Porto in the UEFA Champions League last 16 matches, and the match will end 2-0, 3-0, or 3-1.