Kai Havertz has shared what happened behind the scenes at Arsenal that helped him overcome his early-season slump last year. The German international was a surprise signing for the Gunners last summer as Arsenal shelled out £65m to sign Havertz from Chelsea, with the 24-year-old attacking midfielder having a mixed spell in west London. After a rough start to life with Arsenal, it looked like Mikel Arteta had landed on his first big-money flop since returning to north London as manager, with Havertz struggling to adapt at the Emirates Stadium. Yet the forward eventually found his feet, and Have…