Not sure Wiki is a good source as it states:
In July 2006, he was appointed coach of Serie B side Arezzo. After a series of disappointing results, he was sacked on 31 October 2006.
On 13 March 2007, Conte was reinstated as Arezzo head coach as his predecessor Maurizio Sarri failed to gain any significant improvement with the club mired in a relegation struggle. He subsequently led the team to five consecutive wins, securing 19 points from 7 matches, which allowed the Tuscan side to close the points gap between them and safety. Despite this turnaround in form, Arezzo was relegated to Serie C1 on the final day of the league season, finishing one point behind Spezia.
He then encountered success in the second division of Serie B 2007, which still doesn't have the competitive merit as the first division in the English league. I'm not disclosing that Conte isn't an accredited coach, but Arteta has the pedigree of a world class manager given his trajectory and what he's demonstrating at present being an inexperienced manager. He's also doing what no United manager has achieved in even challenging for the league in a decade with numerate resources in two consecutive seasons.