Playing in front of 40,112 fans, the largest crowd for a football match in New Zealand's history, De Zerbi picked a youthful side captained by Archie Gray before introducing senior players, including Richarlison and Mathys Tel, in the final half hour. Dane Scarlett and Richarlison scored the goals in the 2-0 win.
"Yes, we played seriously, first of all, because when we play for this club or when we work for this club, we have to work in the best way we can. The young players, they played very, very well, especially in the first half, with a clear idea, with the right spirit, with the right qualities as well," De Zerbi said, before highlighting an important piece of news from the game itself.
"In the second half, we played 30 minutes with the older players... We didn't suffer any injuries, and that's big news, important news, especially for the beginning of the season."
Asked about James Maddison's absence from involvement, De Zerbi played down any concern.
"He's not working the last five days, I think, like Udogie, but they have not a big problem, just to stay focused, don't take any risks."
On breakout teenager Luca Williams-Barnett, the head coach was enthusiastic but careful not to overlook the club's wider academy responsibilities: "Luca is a big talent, very young, big talent. Malachi [Hardy] is another good player for the future of the club. We can't forget the young players, especially for the new rules, the financial fair play, or the rules of the Champions League, Europa League. And then we have to improve our academy."
He was similarly warm about captain Archie Gray's influence on the squad's younger players.
"Archie is young, but he's an old player, as a mentality, as a performance, as an experience, as a career... when I decide the players, when I decide the squad, I never see the age of the players. I just analyse the qualities and the potential of these players."
Asked whether Gray might feature at right-back with Pedro Porro and Djed Spence still returning from their World Cup breaks, De Zerbi added: "It's lucky for me when you have these type of players who are able to play in different positions."
On academy winger Mikey Moore's role next season, De Zerbi struck a note of caution: "We have to see. We have to analyse the last part of the transfer market, because we try to bring wingers, and then we speak with him, with his agent, with the club, to find the best solution for everyone."
Turning to the club's transfer business more broadly, De Zerbi made clear the window remains a work in progress.
"We have to finish the window of this transfer market, because it's not finished yet, our transfer market. I think we can be happier at the end of this transfer market, because I spoke a lot of time with the owners, with the board, and they want to build a very strong team for this season for sure, but to make the base for the future to become great again."