5 takeaways from a fascinating weekend of European football

#2 Arsenal’s defence continues to creak

Arsenal's defence is still an issue

Unai Emery may have won his first 3 points as Arsenal manager, but the meticulous Spaniard will be under no illusions as to the size of the rebuilding task awaiting him.

He will be grateful for the 3-1 scoreline, but make no mistake about it; it was a result that greatly flattered The Gunners. West Ham are just as much of a shamble under Manuel Pellegrini as they were last season. But attacking-wise, The Hammers are far better than they were under David Moyes.

Against Arsenal on Saturday, they created many chances and were let down by poor finishing. For The Gunners, Hector Bellerin and Shkodran Mustafi in particular, were poor, they were exposed against the pace of Mikhail Antonio, and the trickery of Felipe Anderson.

Mustafi was given a torrid time by Marko Arnautovic, and had to be bailed out a number of times by defensive partner Sokratis Papastathopoulos and the increasingly influential Mattéo Guendouzi

With Cardiff City to come this weekend, the goal-shy Welsh team are the perfect opponents for The Gunners to get their first clean sheet of the season.