Looking at the odds, Arsenal remains heavy favorite.
It's really worth to bet draw or Porto to win, looking at their previous match, Arsenal was struggling to beat Brentford while Porto is still strong until now. So I expect this match should ends in draw, Porto don't have to win while Arsenal will try their best to win.
I think it is quite risky to bet on a draw or on Porto winning because Arsenal's percentage of being able to turn things around is very large.
Arsenal have quite strong strength at the moment, apart from the hard-fought victory they got against Brentford last weekend, this cannot be used as a reference because they only look at one match, but look at Arsenal's overall performance.
Porto cannot be underestimated, but realistically, Arsenal's strength is much stronger and this match will be played at Emirates Stadium, Arsenal's home ground, so I think it is better to bet on Arsenal winning this match.