Mikel Arteta has only known frustration at Arsenal in the Champions League last 16. When he was a player at the club, he tasted defeat at this stage of the competition in five consecutive seasons – part of a wider run of seven last 16 exits from 2011 to 2017. That was then. But here, after a stressful night in Porto against a team with rather more recent experience of these kind of occasions, when the margins were so excruciatingly thin, Arteta got the same sinking feeling.
Nothing has been decided yet. It was another first-leg battle, defined by defensive tightness, the closing of spaces and perhaps even more by the feeling that neither team wanted to make a mistake; to concede.