Orlando, languishing three places off the bottom of the Eastern Conference with a 17-29 record prior to Monday's game, took full advantage of Boston's injury crisis to complete a deserved win at the Amway Center in Florida.
The league-leading Celtics were missing key defensive figures Marcus Smart and Robert Williams due to injury and their absence proved crucial as a fired-up Orlando stormed to victory.
The 20-year-old Banchero showed a maturity beyond his tender years to orchestrate Orlando's win, which saw five Magic players reach double-digit totals, with Wendell Carter Jr. posting 21 points and Germany's Franz Wagner 15.
"Anytime you get to play a championship-level team, a team that's been to the finals, and has been where you want to be, you want to put out your best effort and get the win," Banchero said afterwards.
"That's my mentality, and that's our team's mentality, and we were able to do that.
"I just wanted to be decisive with my moves, when I decided to attack, when I decided to shoot - not force anything and let the game come to me. Be aggressive and decisive, and live with the results."
Arguably the most impressive contribution came in the form of a 10-minute cameo from Jonathan Isaac, making his first appearance in an NBA game since August 2020 following more than two years dominated by injuries.