It feels like one of those season defining moments when Mikel Arteta’s Arsenal side face FC Porto for their second leg tonight. Having lost in Dragao, Arteta now needs his team to produce a goal-ladened performance they’ve been so accustomed to of late. Arsenal need Kai Havertz and Bukayo Saka to show their class yet again, especially given Gabriel Martinelli will be missing the game. And whilst Arteta has a big selection call to make on the left side of his attack, there’s also several other decisions to be made. Porto are masters of frustration, they’ll be coming to North London to stop thei…