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.
If the match has to continue until the penalty round to find a winner, I think Arsenal has a big chance of getting rid of Porto. But maybe everything will be finished in normal time, what is clear is that this match will be fierce, and Porto will definitely use a defensive strategy and rely on counter-attacks. Mikel Arteta must be very careful in determining his starting XI, experienced players like Jerginho are better played from the early minutes, to read the weaknesses of Porto defense.
If Arsenal are eliminated from the round of 16 it will be very sad, because they have much better depth than Porto, and acting as hosts should be put to good use to turn things around. Everything will be proven tomorrow, how far Arsenal can go, they have to forget the bad history in the round of 16. With consecutive wins in the Premier League, Arsenal now has good confidence ahead of the second leg.