Roma is not that strong and they're not stable but if they take this match very serious, they can achieve victory. Porto isn't a strong team too and I believe that whoever among these two clubs that can outplay the other will definitely qualify to the round of 16. I will both clubs have the same strength and it's a perfect match.
Both teams will build attacks very well because it is about who will qualify for the next round and who will be eliminated in this season in the Europa League early. So I also think that the Porto vs Roma match will be a pretty fierce match for these two teams because apart from their respective strengths, it is also about how they implement their best strategy in the match so that they do not lose badly. But I want to see Roma advance to the next round so that Roma can have the spirit to continue competing with stronger teams in the next round.
Actually there is nothing special about the two teams that will meet, although Porto is more trusted to win, but I see nothing special about their game. I also agree that Porto is better than AS Roma on paper, but that is not a guarantee that they will be able to win this match. AS Roma is designing a new strategy and slowly they are getting a good game, although not completely good. But at least it can be capital for them to grow their confidence. The result might be a victory when they play at home, be it Porto or AS Roma, so in the end they will determine the position with the aggregate.