The Nigerian winger was named man of the match after playing a central role in each of AC Milan's four goals as Rúben Amorim's side came from behind twice to beat United, capping their pre-Serie A schedule with their most convincing performance of the summer.
Speaking to La Gazzetta dello Sport after the match, Chukwueze reflected on his current form and the team's readiness for the season ahead.
"Of course, I'm very happy. It was a good test for the team, to prepare us for the season. We did everything perfectly. I think we need to keep working hard ahead of the season and the next match, the first one in Serie A, against Torino."
Chukwueze also addressed his relationship with head coach Amorim, who has entrusted him with regular minutes since his return from a season on loan at Fulham.
"He's a good coach. He trusts me and that's why he's given me an opportunity. Now it's up to me to take it… He's simply given me confidence and I think I have to make the most of it. I mustn't waste this once-in-a-lifetime chance, which is coming back to Milan after the loan."
Asked whether he had settled into his new role as a wing-back in Amorim's system, the 27-year-old admitted the adjustment was still a work in progress.
"Yes, even though it's a position I have to adapt to because I've never played this role in my career. As a player, if a coach wants you to play in this position, you have to do it believing in yourself and in the coach too, because he knows what he wants.
"So I just have to keep working hard, believing in myself and in the fact that I can do it. For me it's an opportunity I have to take. I know it's a difficult task, but I believe in myself. I know I can do it, that I can do anything."
On his overall satisfaction with how the new-look Milan side is shaping up, Chukwueze pointed to continued improvement in training.
"Yes, a lot. For me I think it's something I have to work on. It's the first time I've played in this position, so I keep working hard. Every training session I have to improve. I think the coaching staff are helping me. The coach is helping me too. Every time I make a mistake, he tells me: 'Oh, Chukwueze, this is what you need to do.' So I think I'll improve before the start of the season."
Reflecting on the win itself, Chukwueze credited the group's preparation over the past week: "I'm very happy and so is the team. We've worked hard all week and we're preparing well for the season. We want to start Serie A with a win, to have the confidence that everyone needs. It's essential that the fans and the club believe in us too."
He also had warm words for new strike partner Gonçalo Ramos, who scored his first goal for the club in the win.
"I think he's a fantastic striker, one you want to play with. He knows when to come short, he's good in the air and he attacks the space behind defenders. I think he's a fantastic guy."