Perhaps Mikel Arteta’s Arsenal squad will have been focusing on one key discipline in training before they face Liverpool on Sunday. Arteta’s side bossed Liverpool in the FA Cup at the Emirates, only to be let down by their wayward finishing. If Jurgen Klopp’s side were clinical on the day, Arsenal were the exact opposite. Kai Havertz enjoyed a strong performance as Arsenal’s striker, but ultimately couldn’t finish his chances. And perhaps one solution Arteta has sought, was to have his squad training at Emirates Stadium on Saturday, a rarity this season. Perhaps the Spaniard wants his Arsenal…