It’s almost hard to remember the days when Kai Havertz was struggling at Arsenal, failing to quite grasp the number eight role under Mikel Arteta. Havertz is now flying as a number nine in north London, a striker who has already scored two goals in three appearances for Arsenal this season. It’s evident that the German is more comfortable playing further forward, a position he often plays for his country too. However, on Saturday evening against Hungary, Julian Nagelsmann decided to deploy Havertz in a number 10 role, a blast from the past. Havertz used to play in the 10 often for Bayer Leverk…