Christian Norgaard, a new signing from Brentford, made his first appearance for the Gunners, while fellow arrivals Kepa Arrizabalaga and Martin Zubimendi started on the bench. The match was played in front of a crowd of over 22,800 fans.
Arsenal, who finished as runners-up in the English Premier League for the past three seasons, looked more lively in the first half, dominating possession but failing to convert their chances. Arteta made six changes at the break, introducing Arrizabalaga and Zubimendi to the team.
The breakthrough came just seven minutes into the second half, as Bukayo Saka scored with a shot from a cross by Jakub Kiwior. Saka was later named Man of the Match and made way for 15-year-old Max Dowman, a product of the club academy.
Arsenal continued to press for a second goal, but AC Milan's substitute goalkeeper Lorenzo Torriani made a crucial save from Mikel Merino's header in the 75th minute. He was called into action again seven minutes later, tipping Leandro Trossard's close-range effort over the bar.
Manager Arteta expressed his satisfaction with the team's performance, saying, "I'm very happy with the attitude and domination we showed throughout the game. But there are always things to improve." He also mentioned that he needs to find cohesion within the players and for them to step up to the next level.
The Londoners will next face fellow Premier League side Newcastle on Sunday.