Manchester City boss Pep Guardiola believed Mikel Arteta would become an outstanding manager when he left the club to take charge of Arsenal - and this opinion has not changed despite the north London outfit's poor start to the season. City breezed past the Gunners 4-1 in the Carabao Cup (December 22) to add more pressure on Arteta whose team are languishing near the bottom of the Premier League table in 15th place.