Patrick taking a bite of the churro and letting Art take one was unscripted. Josh O'Connor was starving and it was the first time he ever had churros.
Majority of the tennis balls hit during the movie are CGI, as it was too difficult to achieve the cinematic style using real balls.
To prepare for her role, Zendaya spent three months with pro tennis player-turned-coach, Brad Gilbert.
The New Rochelle Umpire is played by Darnell Appling, Zendaya's close friend and personal assistant. To prepare for his role, Appling took professional umpire lessons.
Austin Butler and Timothée Chalamet were considered for the role of Art Donaldson before Mike Faist was cast.