Mikel Arteta had promised that this week would be the acid test of how much Arsenal have improved this season and, on the evidence of this scrappy performance, they still have plenty to work on.

But after overcoming the first hurdle against Tottenham on Sunday, it needed a miraculous double save from David Raya to rescue them from defeat in the opening match of their Champions League campaign after a disjointed display that only underlined just how much they are missing captain Martin Ødegaard.